CN121203395A - Transferable liquid confined aerogel film and preparation method and application thereof - Google Patents

Abstract

This invention provides a transferable liquid-confined aerogel film, its preparation method, and its applications. The transferable liquid-confined aerogel film comprises an aerogel film and a liquid material, wherein the liquid material is saturated and filled within the aerogel film, forming a saturated liquid layer on the surface of the aerogel film. The viscosity of the liquid material is below 500 mPa·s, and its static contact angle with the aerogel film is below 40°. The liquid-confined aerogel film provided by this invention exhibits excellent transferability and can be conformally attached to substrates of various materials and shapes. It also possesses tunable optical transparency, efficient terahertz wave absorption performance, excellent flexible sensing capabilities, and anti-fouling properties.

Description

Transferable liquid confined aerogel film and preparation method and application thereof

Technical Field

The invention belongs to the technical field of aerogel film materials, and particularly relates to a transferable liquid confined aerogel film, a preparation method and application thereof.

Background

Aerogel is an emerging three-dimensional nano porous material, and by virtue of the unique properties of ultra-high porosity, ultra-low density, large specific surface area, extremely low thermal conductivity and the like, the aerogel is widely focused in the fields of heat insulation, environmental remediation, catalysis, energy storage and conversion, biomedicine and the like. The aerogel film has excellent mechanical property, chemical stability and thermal stability, can be used as a self-supporting solid matrix with flexibility and rigidity, and provides abundant limited space for functional liquid. The nano structure, high porosity and large specific surface area of the composite material make the composite material become an ideal carrier of the liquid with the finite field function, so that a series of novel aerogel finite field solid-liquid composite materials are derived. The materials have the characteristics of pollution resistance, drag reduction, optical transparency, intelligent response, selectivity and the like, and have breakthrough application values in the fields of separation, adsorption, micro-fluid control, heat management, electromagnetic protection and the like. For example, the prior art ZL202210683518.4 discloses an aramid aerogel/uranium extraction liquid composite membrane, which realizes efficient seawater uranium extraction performance under dynamic interface disturbance, and has excellent solid-liquid interface stability, solid-liquid interface adhesion and high ion selectivity. The prior art 202311360008.4 discloses an in-situ liquid limited aramid aerogel solid-liquid composite membrane, which can realize on-demand switching of opposite functions on a single membrane material by regulating and controlling driving pressure, wherein emulsion with adjustable, uniform and stable particle size can be formed in an emulsion mode, oil and water can be efficiently separated from an emulsion and an oil-water mixture with any proportion in a demulsification mode, and the membrane has excellent anti-fouling performance. The prior art ZL202011621418.6 discloses an aramid aerogel/phase change fluid composite membrane which exhibits excellent thermal rectification characteristics and is suitable for flexible thermal management.

Although the aramid aerogel film has been remarkably developed, development of a film layer which is excellent in mechanical properties, ultra-thin in thickness (for example, the thickness is less than 10 mu m) and transferable is still challenging, and the main reasons are that 1. Static electricity interference is that the surface of the aramid aerogel is provided with a large amount of static electricity, when the aramid aerogel is transferred to a target substrate, the ultra-thin film is difficult to be integrally and conformally attached to the surface of the substrate due to the static electricity effect, and 2. Mechanical weakness is that when the thickness of the aramid aerogel film is small (for example, the thickness is less than 10 mu m), the crosslinking density of an aerogel network is low, the mechanical property of the aramid aerogel is remarkably weakened, and the aramid aerogel is easy to break in use.

Disclosure of Invention

In order to solve all or part of the technical problems, the invention provides the following technical scheme:

a first aspect of the invention provides a transferable liquid confinement type aerogel film comprising:

An aerogel film;

And a liquid material which is filled in the aerogel film in a saturated manner, forms a saturated filling liquid layer on the surface of the aerogel film, and has a viscosity of 500 mPa-s or less and a static contact angle with the aerogel film of 40 DEG or less.

According to the invention, the liquid material with low viscosity (below 500 mPa s) and good wettability is filled in the aerogel film to form the saturated filling liquid layer, so that the obtained liquid confinement type aerogel film has good transferability and can be attached to the surfaces of substrates with various materials and various shapes. It is noted that the surface of the liquid confinement aerogel film needs to be guaranteed to be filled with a saturated liquid layer to form a 'liquid submerged' structure, so that good transfer performance can be guaranteed. And if the viscosity of the liquid material is too high, the film is difficult to transfer smoothly, and if the static contact angle of the liquid material and the aerogel film is too high, the functional liquid is difficult to infiltrate the film material, the film is difficult to transfer completely, and the film is easy to break.

In some embodiments, the aerogel film comprises an aramid aerogel film, a cellulose aerogel film, a polyimide aerogel film, or a silica aerogel film.

In a partially preferred embodiment, the aerogel film is an aramid aerogel film. The surface of the aramid aerogel film is provided with a large amount of static electricity, when the aramid aerogel film is transferred to a target substrate, an ultrathin film is difficult to be integrally and co-molded on the surface of the substrate due to the action of the static electricity, the aramid aerogel film is filled with a liquid material with the viscosity of less than 500 mPa s and the static contact angle with the aerogel film of less than 40 degrees, the selected liquid material needs to have excellent solid-liquid interface wettability with the aramid aerogel film and is saturated and filled with a porous to form a 'liquid submerged' structure, namely, the surface of a solid porous material can be similar to the surface tension polarity of the liquid material, but the liquid material cannot have obvious damage or swelling effect on an aerogel framework, so that the liquid material has the characteristic of being capable of being integrally and efficiently transferred to the substrate, and can be co-molded on the surfaces of substrates with various shapes.

In some embodiments, the transferable liquid confinement type aerogel film comprises a polymer network skeleton composed of aramid nanofibers and liquid materials uniformly distributed in the polymer network skeleton, wherein the aramid nanofibers are lapped to form a three-dimensional porous network structure, and the three-dimensional porous network structure can provide strong capillary force for the liquid materials, stably confine the liquid materials, and enable the liquid materials to be filled and embedded in the polymer network skeleton.

In some embodiments, the aerogel film has a thickness of 200 nm to 300 μm.

In some embodiments, the aerogel film has a three-dimensional porous network structure, the three-dimensional porous network structure comprises micropores with a pore diameter of less than 2 nm and mesopores with a pore diameter of 2-50 nm, and the porosity of the three-dimensional porous network structure contained in the aerogel film is 75-99%.

In some embodiments, the aerogel film, such as an aramid aerogel film, has a pore size of 10 nm to 50 nm, a porosity of 80% to 99.5%, and a specific surface area of 200m ²/g~350 m²/g.

In some embodiments, the liquid material comprises one or more of water, a phase change fluid, an ionic liquid, or a silicone oil.

In some embodiments, the phase change fluid comprises a positive temperature-dependent phase change fluid or a negative temperature-dependent phase change fluid. At this time, the liquid-confinement aerogel film has not only good transferability but also temperature-dependent optical properties and good flexibility. The phase-change fluid with positive temperature correlation is in a liquid state at room temperature, can be wrapped on a framework formed by connecting nano materials of an aerogel film, and is embedded in a three-dimensional porous network structure. The phase-change fluid with the negative temperature is solid at room temperature, is heated to the phase-change temperature, is wrapped on a skeleton formed by connecting nano materials, and is embedded in a three-dimensional porous network structure. When the liquid material is a phase-change fluid related to positive temperature, the transparency of the liquid confined aerogel film is reduced along with the temperature rise, and when the liquid material is a phase-change fluid related to negative temperature, the transparency of the liquid confined aerogel film is increased along with the temperature rise.

Further, the positive temperature-dependent phase change fluid comprises one or more of poly (N-isopropyl acrylamide) (PNIPAm), hydroxypropyl cellulose, and poly (N-vinyl caprolactam) (PNVCL).

Further, the negative temperature-dependent phase change fluid comprises one or more of eicosane, 1-octadecane and octacosane.

In some embodiments, the ionic liquid comprises one or more of 1-octyl-3-methylimidazole bistrifluoromethanesulfonimide salt, 1-hydroxyethyl-3-methylimidazole bistrifluoromethanesulfonimide salt, tetrabutylammonium 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester salt, 1-butyl-3-methylimidazole bistrifluoromethanesulfonimide salt.

In some embodiments, the silicone oil includes one or more of a dimethyl silicone oil having a viscosity of 100 to 500 mpa·s.

The surface tension polarity of water, the phase-change fluid, the ionic liquid and the silicone oil which are specifically selected are similar to the surface energy of the aramid aerogel film, the liquid materials can be used for saturatively filling the porous structure of the aramid aerogel film, and a saturated filling liquid layer is formed on the surface of the aramid aerogel film, so that a 'liquid submerged' structure is formed, and the aerogel framework is not damaged or swelled obviously.

In a typical embodiment, the liquid material comprises 1-octyl-3-methylimidazole bistrifluoromethylsulfonylimine salt. At this time, the liquid-confinement aerogel film not only has good transferability, but also has improved mechanical tensile properties, and can maintain good integrity during transfer or use when the thickness of the liquid-confinement aerogel film is small (for example, the thickness is less than 10 μm, even when the thickness is nano-scale). In addition, the liquid confinement type aerogel film filled with the 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl imide) salt also has good optical transparency and terahertz wave absorption performance, and has excellent anti-fouling performance.

A second aspect of the present invention provides a method for preparing a transferable liquid confinement type aerogel film as set forth in any one of the preceding claims, the method comprising:

Coating nano primitive dispersion liquid on a substrate, and sequentially carrying out sol-gel conversion, solvent replacement and drying treatment to form an aerogel film, wherein the nano primitive dispersion liquid contains nano precursor materials required for forming the aerogel film;

and (3) saturating and filling a liquid material into the porous structure of the aerogel film, and forming a saturated liquid filling layer on the surface of the aerogel film, so as to obtain the transferable liquid confinement type aerogel film, wherein the viscosity of the liquid material is below 500 mPa.s, and the static contact angle of the liquid material with the aerogel film is below 40 degrees.

According to the porosity of the membraneAnd its volume V _{Film and method for producing the same} , calculating the theoretical functional liquid volume required to fill all pores, the required volume of liquid material V _Liquid being greater than×V _{Film and method for producing the same} 。

In some embodiments, the nano primitive dispersion liquid comprises aramid nanofibers, alkali, methanol and a solvent, wherein the concentration of the aramid nanofibers is 1-2 wt%, the mass ratio of the aramid nanofibers to the alkali is 1:0.5-1:1.5, and the concentration ratio of the aramid nanofibers to the methanol is 1:0-5. The viscosity of the nano-primitive dispersion can be adjusted by adjusting the concentration of the aramid nano-fibers and/or the methanol, and the viscosity of the nano-primitive dispersion is more suitable when the concentration is within the above range. The alkali may be potassium tert-butoxide and/or potassium hydroxide, and the solvent may be dimethyl sulfoxide and/or concentrated sulfuric acid, for example.

In some embodiments, the nano-primitive dispersion is coated on the substrate by spin coating, wherein the spin coating speed is 500-9500 rpm, and the spin coating time is 30-90 s.

Further, the spin coating speed is preferably 2500-6500 rpm. The aerogel film obtained by spin coating has good integrity and excellent optical transparency.

In some embodiments, the drying process comprises supercritical drying or freeze drying.

In an exemplary embodiment, the method of preparing includes:

(1) And mixing and stirring the aramid nanofiber, dimethyl sulfoxide, potassium tert-butoxide and methanol to prepare an aramid nanofiber dispersion, wherein the mass percentage of the aramid nanofiber is 1-2 wt%, the mass ratio of the aramid nanofiber to the potassium tert-butoxide is 1:1, and the mass ratio of the aramid nanofiber to the methanol is 1:0-4.

(2) Uniformly coating the aramid nanofiber dispersion liquid on a substrate through a spin coater, carrying out protonizing reduction and full solvent replacement on the coated film in an aqueous solution, and then obtaining the aramid aerogel film through supercritical drying, wherein the rotating speed of the spin coating process is 500-9500 rpm, and the spin coating time is 30-90 s.

(3) And filling the liquid material into the aramid aerogel film by adopting a dipping filling mode.

The thickness of the aramid aerogel film can be regulated and controlled by regulating one or more conditions of the viscosity of the aramid nanofiber dispersion liquid, the volume of the aramid nanofiber dispersion liquid adopted in spin coating, the spin coating rotating speed and the substrate size, wherein the thickness can be any point value or a thickness range formed by any two point values of 200 nm, 1 mu m, 10 mu m, 100 mu m, 300 mu m and the like.

A third aspect of the invention provides the use of a transferable liquid confinement aerogel film of any one of the preceding claims in flexible optical displays, terahertz electromagnetic shielding or flexible sensing.

A fourth aspect of the invention provides a flexible sensor comprising a transferable liquid confinement aerogel film according to any one of the claims.

In a fifth aspect, the present invention provides an application of the transferable liquid confinement aerogel film in terahertz electromagnetic shielding, where the liquid material contained in the transferable liquid confinement aerogel film includes 1-octyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt.

A sixth aspect of the present invention provides a terahertz wave absorbing structure, which includes the transferable liquid confinement aerogel film, the liquid material included in the transferable liquid confinement aerogel film includes an ionic liquid including one or more of 1-octyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, 1-hydroxyethyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, tetrabutylammonium 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester salt, and 1-butyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt.

In some embodiments, the mass percentage of the ionic liquid is 70 wt-85 wt% of the total mass of the transferable liquid confinement type aerogel film, and the thickness of the aerogel film is 6.0-20.0 μm. At the moment, the terahertz wave absorption effect is excellent, and if the filling amount of the ionic liquid is small or the thickness of the film is lower than 6.0 mu m, the terahertz wave absorption effect is not obvious.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) The liquid confined aerogel film provided by the invention has good transferability and can be attached to the surface of a substrate or the surface of skin in any shape;

(2) According to the invention, by filling the aerogel film with a proper liquid material, the mechanical tensile strength of the obtained liquid confined aerogel film is improved by the simple aerogel film, so that the integrity of the film is improved in the transferring or using process, and particularly, the film is not easy to crack when the thickness of the film is smaller.

(3) According to the invention, the liquid confined aerogel film with both optical transparency and terahertz wave absorption performance is obtained by filling the ionic liquid, particularly 1-octyl-3-methylimidazole bistrifluoromethanesulfonimide salt, in the aerogel film, and the liquid confined aerogel film can be applied to the field of terahertz electromagnetic shielding, for example, used for preparing structures and equipment with terahertz wave absorption functions.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.

FIG. 1a is a schematic flow chart of a spin coating process for preparing an aramid aerogel film according to an exemplary embodiment of the invention;

FIG. 1b is a schematic flow chart of a process for preparing a liquid-confined aerogel film in accordance with an exemplary embodiment of the present invention;

FIGS. 2a and 2b are respectively physical diagrams of different shapes of the aramid aerogel film in the embodiment 1 of the invention, and FIGS. 2c and 2d are cross-sectional morphology diagrams of the aramid aerogel film shot by a scanning electron microscope;

FIG. 3a is a graph of the viscosity of a dispersion containing different mass fractions of aramid nanofibers in example 4;

FIG. 3b is a graph showing the viscosity of the dispersion of aramid nanofibers with varying amounts of methanol added in example 4;

FIG. 3c is a graph comparing the viscosity curves of a 2 wt% aramid dispersion containing different mass ratios of aramid staple fibers to methanol (m: n, m=1, n=1 to 4) versus a aramid dispersion containing no methanol (1 wt% to 1.5 wt.%);

FIGS. 4a, 4b and 4c are, respectively, spin-coating process of 1wt%, 1.5 wt% and 2wt% concentration aramid nanofiber dispersion observed with a high-speed camera in example 4;

Fig. 5a, 5b, and 5c are physical photographs of aramid aerogel films formed by 1 wt%, 1.5 wt%, and 2 wt% of the aramid nanofiber dispersion in example 5, respectively, under different spin-coating parameters;

Fig. 6a, 6b and 6c are graphs showing the transmittance of the aramid aerogel films obtained by spin coating the aramid nanofiber dispersion of 2 wt% by volume of 1 mL, 3 mL and 5mL in example 5 at different rotation speeds in the visible light band (left side) and the ultraviolet band (right side), respectively;

FIG. 7 is a cross-sectional view and a statistical plot of thickness of films spin-coated at various volumes and speeds for 1 wt% aramid nanofiber dispersion in example 5;

FIG. 8a is a photograph showing the transfer of the liquid-confined aerogel film of example 6 to the surface of glass sheets, metal screens, and polymeric porous foam substrates, FIG. 8b is a photograph showing the transfer of the liquid-confined aerogel film of example 6 in water and to the glass sheet plane and glass article curved surface, FIG. 8c is a photograph showing the transfer of the liquid-confined aerogel film to the surface of spheres, regular octagons, penrose triangles, and three-dimensional Einstein Luo Senqiao, FIG. 8d is a photograph showing the transfer of the liquid-confined aerogel film to the surface of cubes and irregularly shaped objects, and FIG. 8e is a photograph showing the composite film filled with a liquid material having an excessively high viscosity and the composite film formed by the unsaturated filling of the liquid material;

FIG. 9 is a graph showing the change in film transparency of a liquid confinement aerogel film filled with PNIPAm in example 7 of the present invention during heating and cooling;

FIG. 10 is a graph showing the change in film transparency of eicosane-filled liquid confinement aerogel films of example 7 of the present invention during heating and cooling;

FIG. 11 is a graph showing the absorption effect of the liquid-confinement type aerogel film on terahertz waves in example 8 of the present invention;

FIG. 12 is a mechanical tensile stress-strain plot of the liquid confinement aerogel film and the pure aramid aerogel film in example 9 of the present invention;

FIG. 13 is a plot of the repeated folding and resistance change rate of the liquid-confined aerogel film flexible sensor of example 10 of the present invention;

FIG. 14 is a graph showing the finger straightening-bending motion of the liquid confinement type aerogel film flexible sensor of example 11 of the present invention when the sensor is worn on the index finger;

FIG. 15 is a graph of the sensory properties of the liquid-confined aerogel film at the wrist of example 12 of the present invention;

FIG. 16 is a photograph of the liquid-confined aerogel film of example 13 immersed in a black oil-based magnetic fluid and taken out after washing.

Detailed Description

The following detailed description of the present invention is provided in connection with specific embodiments so that those skilled in the art may better understand and practice the present invention. Specific functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed embodiment.

In addition, unless otherwise specified, various materials used in the examples below were purchased from commercial sources, and various production and test equipment used were all known in the art, and test methods used were any known in the art.

Example 1

Preparation and characterization of an aramid aerogel film:

fig. 1a is a schematic flow chart of the preparation of the aramid aerogel film according to this embodiment, which is specifically as follows:

mixing 5g aramid nanofibers, 5g potassium tert-butoxide, 5g methanol and 235 g dimethyl sulfoxide, stirring to uniformity by using a mechanical stirrer to obtain 2wt% aramid nanofiber dispersion, and standing for 4h to remove bubbles for later use;

The preparation method comprises the steps of spin-coating an aramid nanofiber dispersion liquid into a film by using a spin coater, wherein parameters of the spin coater are firstly set, such as a rotating speed of 5500 rpm, a time length of 50 s, an acceleration of 500, then a glass wafer with a size of 80 and mm is placed on a sucker of the spin coater, 3ml of the aramid nanofiber dispersion liquid is injected on the glass wafer by using an injector/a pipette gun, spin coating film preparation is started, after spin coating is finished, an aramid hydrogel film attached to the glass wafer is placed in deionized water for gelation, the aramid hydrogel film is further subjected to solvent displacement by using deionized water, after deionized water is displaced for two times approximately at intervals of 2 hours, ethanol is used for displacement, after each interval of 3 and h, the aramid hydrogel film is displaced for three times by using ethanol, and then the aramid hydrogel film is placed in supercritical for supercritical drying, so that the aramid aerogel film is obtained.

The mass percentage of the aramid nanofibers in the aramid aerogel film is 1 wt% -2 wt%, and the size of the aramid nanofibers is 45 mm, 80 mm and the like. And shearing and tearing the long-strip aramid aerogel film with a certain size from the glass substrate, performing brittle fracture in liquid nitrogen to obtain a neat film material section, and observing the cross section morphology of the aramid aerogel film by a scanning electron microscope. Fig. 2a and 2b are respectively physical diagrams of different shapes of the aramid aerogel film in the present embodiment, and fig. 2c and 2d are cross-sectional morphology diagrams of the aramid aerogel film photographed by a scanning electron microscope.

Example 2

Preparation of cellulose aerogel film:

mixing 5g absorbent cotton balls and 245 g of 1-allyl-3-methylimidazole chloride, stirring uniformly by using a mechanical stirrer to obtain 2 wt% cellulose dispersion, and standing for 4 h to remove bubbles for later use;

The method comprises the steps of spin-coating cellulose dispersion liquid to form a film by using a spin-coating machine, wherein parameters of the spin-coating machine are firstly set, such as the rotating speed is 3500 rpm, the duration is 50 s, the acceleration is 150, then a glass wafer with the size of 80 and mm is placed on a sucker of the spin-coating machine, the cellulose dispersion liquid of 3 ml is injected on the glass wafer by using a syringe/a pipette, spin-coating film preparation is started, after spin-coating is finished, a cellulose hydrogel film attached to the glass wafer is placed in ethanol to carry out gelation, the cellulose hydrogel film is further replaced by ethanol, after each interval is 3 and h, the cellulose hydrogel film is replaced by ethanol for four times, and then supercritical drying is carried out on the cellulose hydrogel film, so that the cellulose aerogel film is obtained.

Example 3

Preparation of silica aerogel film:

sequentially adding 12 ml benzoic acid (BzOH), 5 ml polyvinyl trimethoxysilane (PVTMS), 1080 ul deionized water and 280 ul tetramethyl ammonium hydroxide (TMAHH) into a container, mixing and stirring uniformly by using a magnetic stirrer to obtain gel precursor solution, and standing for 4: 4h to remove bubbles for later use;

The method comprises the steps of setting parameters of a spin coater, namely, rotating speed 600 rpm, time length 30 s and acceleration 60 rpm/s, placing a glass wafer with a size 40 mm on a sucker of the spin coater, injecting gel precursor solution of 3 ml on the glass wafer by using an injector/a pipette, starting spin coating to form a film, placing a silica gel film attached to the glass wafer in air to carry out gel 12h after spin coating, further aging by using benzyl alcohol, approximately aging for 24h, starting replacement by using absolute ethyl alcohol, replacing four times by using absolute ethyl alcohol after each interval 3 h, and then placing the silica gel film into supercritical for supercritical drying to obtain the silica gel film.

Example 4

Influence of concentration of aramid nanofiber dispersion on spin coating process, morphology transparency, integrity and the like of aramid aerogel films:

1) The mass percentages of the prepared aramid nanofiber are respectively 1 wt percent, 1.5 wt percent and 2 wt percent, and the prepared aramid nanofiber dispersion of 250 g is taken as an example and specifically comprises the following steps:

① 1 wt% aramid nanofiber dispersion, namely mixing 2.5 g aramid nanofibers, 2.5 g potassium tert-butoxide, 2.5 g methanol and 242.5 g dimethyl sulfoxide, stirring uniformly by using a magnetic stirrer to obtain 1 wt% aramid nanofiber dispersion, and standing the casting film solution for 4h to remove bubbles for standby.

② 1.5 Wt% of aramid nanofiber dispersion liquid, namely mixing 3.75 g of aramid nanofibers, 3.75 g of potassium tert-butoxide, 3.75 g of methanol and 238.75 g of dimethyl sulfoxide, stirring uniformly by using a magnetic stirrer to obtain 1.5 wt% of aramid nanofiber dispersion liquid, and standing the casting film liquid for 4h to remove bubbles for standby.

③ 2 Wt% of aramid nanofiber dispersion liquid, namely mixing 5g aramid nanofibers, 5g potassium tert-butoxide, 5g methanol and 235 g dimethyl sulfoxide, stirring uniformly by using a mechanical stirrer to obtain 2 wt% of aramid nanofiber dispersion liquid, and standing the casting film liquid for 4 h to remove air bubbles for later use.

2) Influence of mass percentage of aramid nanofibers in aramid nanofiber dispersion on viscosity

The aramid nanofiber dispersion solutions with different mass percentages are taken to be 1 ml respectively, and the change of viscosity along with the shear speed is tested by using a rotary rheometer. Fig. 3a is a graph for testing rheological behavior of an aramid nanofiber dispersion containing different mass percentages of aramid nanofibers, and as shown in fig. 3a, it can be seen that the above-mentioned aramid nanofiber dispersions with different mass percentages all have a phenomenon of shear thinning, and as the mass concentration of the aramid nanofibers is greater, the rate of shear thinning increases, and as the mass percentage of the aramid nanofibers increases, the viscosity thereof also increases.

3) Influence of methanol concentration on viscosity of aramid nanofiber dispersion

Taking 2 wt% of aramid nanofiber dispersion as an example, changing the concentration of methanol added in the aramid nanofiber dispersion to prepare the dispersion with the mass ratio of 1:0 (no methanol added), 1:1, 1:2, 1:3, 1:4 and 1:5 respectively, wherein fig. 3b is a flow deformation test chart of the aramid nanofiber dispersion with different methanol addition amounts, as shown in fig. 3b, the color of the aramid nanofiber dispersion is changed from dark red to light red along with the increase of the methanol content, the rheological property characteristics are consistent when the mass ratio of the aramid nanofiber to the methanol is 1:1 and 1:2, and the viscosity thinning rate is larger than that when the mass ratio of the aramid nanofiber to the methanol is 1:3 and 1:4 in the later period, and the rheological property characteristics are consistent. Fig. 3c is a graph comparing viscosity curves of a 2wt.% aramid dispersion with a different mass ratio of aramid nanofibers to methanol (1:1, 1:2, 1:3, 1:4) to a non-methanol containing aramid dispersion (1 wt wt.% to 1.5 wt.%), as can be seen from fig. 3c, in the earlier stage, the viscosity of a dispersion containing 2wt wt.% aramid (aramid nanofibers: methanol=1:1) was thinned simultaneously with the aramid nanofibers: methanol=1:2, and the viscosity was similar. The viscosity was, in order from large to small, 2 wt% dispersion (aramid nanofibers: methanol=1:1, 1:2), 1.5: 1.5 wt% dispersion (without methanol), 2 wt% dispersion (aramid nanofibers: methanol=1:3), 2 wt% dispersion (aramid nanofibers: methanol=1:4).

If the viscosity of the aramid nanofiber dispersion is too high, the dispersion is difficult to spread smoothly during spin coating, so that a film with a thinner thickness cannot be formed, if the viscosity is low, continuous forming of the film is poor, so that from the aspect of proper viscosity, the mass percentage of the aramid nanofiber is in the range of 1-2 wt%, if methanol is added, the content of the aramid nanofiber can be 2 wt%, and the mass ratio of the aramid fiber to the methanol is in the range of 1:1-1:4.

4) Influence of mass percentage of aramid nanofibers in aramid nanofiber dispersion on spin coating process, morphology transparency, integrity and the like of aramid aerogel film

Fig. 4a, 4b, and 4c are the spin coating process of the aramid nanofiber dispersion prepared in this example at concentrations of 1wt%, 1.5wt%, and 2wt%, respectively, as observed with a high-speed camera. The aramid nanofiber dispersion can observe a large amount of wavy liquid during spreading, and when radially spread, a thin inner film is formed in the middle, and capillary ridges are formed on the periphery. Due to the difference in viscosity due to the different concentrations of the aramid nanofiber dispersion, the film spread rate was different at the same rotational speed, and a comparison of fig. 4a-4c shows that at 13s, for 1wt% and 1.5. 1.5wt% of the aramid nanofiber dispersion, it had been spread over the entire substrate, whereas 2wt% of the aramid nanofiber dispersion had been spread over only about 2/3.

Example 5

Influence of volume and rotation speed of aramid nanofiber dispersion on aramid aerogel film:

According to the controlled variable method, 1 wt%, 1.5 wt% and 2 wt% of the aramid nanofiber dispersion prepared in example 2 of 1 ml, 3 ml and 5 ml were used to investigate the effect on the integrity, optical transparency and thickness of the film at different rotational speeds (rotational speed is adjustable in 500-9500 rpm).

Fig. 5a, 5b and 5c are physical photographs of an aramid aerogel film formed by 1 wt%, 1.5 wt% and 2 wt% of an aramid nanofiber dispersion under different spin-coating parameters, respectively, and the integrity of the film is judged according to whether the shape of the film is a regular circle and whether the film is broken or not (v represents that the integrity of the film is good, x represents that the integrity is poor).

As can be seen by referring to fig. 5a-5c, the volume of the aramid nanofiber dispersion was 1 ml at a lower rotational speed (500 rpm), the whole substrate was not fully coated, and the film was spin coated uniformly at a low concentration (1-1.5 wt.%) with increasing rotational speed. For an aramid nanofiber concentration of 2 wt%, an aramid nanofiber dispersion of 1 ml would need to be spun at 2500 rpm to be uniform. The aramid nanofiber dispersion liquid with v=1 ml is susceptible to breakage and uneven thickness under the conditions of high rotation speed (5500-9500 rpm) and low concentration (1 wt.%).

Fig. 6a, 6b and 6c are graphs showing the transmittance of the aramid aerogel film obtained by spin coating the aramid nanofiber dispersion liquid of 2 wt% in volumes of 1mL, 3mL and 5mL at different rotation speeds in the visible light band (left side) and the ultraviolet band (right side), respectively. In general, the aramid aerogel film has the characteristics of visible light transparency and ultraviolet light wave band opacity, the transparency of the visible light wave band is 89-96.5%, and the transparency of the ultraviolet light wave band is 0.2-1.8%. As can be seen from fig. 6a, 6b, and 6c, the film has an increased transmittance in the visible light range with an increase in the rotation speed, and can be transparent as the glass substrate. In the ultraviolet band, the transmittance of the film to the ultraviolet band is enhanced along with the increase of the rotating speed.

The thickness of the aramid aerogel film spun by adopting an electron microscope to represent the approximate thickness of the aramid nanofiber dispersion liquid spun by 1 wt percent, taking 5 points for each section to test the thickness, and finding that when the aramid nanofiber dispersion liquid spun by 1 mL is taken, the thickness of the film spun by adopting a rotating speed of 1500-2500 rpm is less than 540 nm under the condition of ensuring the integrity of the film, when the aramid nanofiber dispersion liquid spun by 3mL is taken, the thickness of the film spun by adopting a rotating speed of 1500-3500 rpm is less than 2 mu m under the condition of ensuring the integrity of the film, and when the aramid nanofiber dispersion liquid spun by 5 mL is taken, the thickness of the film spun by adopting a rotating speed of 1500-4500 rpm is less than 3 mu m under the condition of ensuring the integrity of the film. The integrity and thickness of the spin-coated film is shown in fig. 7, where the spreading of the film on the rotating substrate is affected by the balance control between kinetic energy, surface energy, viscous dissipation energy, and the shear work exerted by the rotating substrate on the droplets.

Example 6

Liquid-confined aerogel films with excellent transferability

The aerogel film spin-coated on the glass substrate takes the aramid aerogel film as an example, the aramid aerogel film is lifted from the substrate, the film is easy to bend, strong static electricity is easy to generate, and especially nitrogen anions can be exposed on the surface of the aramid aerogel film. The test shows that the mass fraction of the aramid aerogel film is 1.5-2 wt%, the spin coating speed of the aramid aerogel film is 500-3500 rpm, the charging amount of the lower surface of the aramid aerogel film contacting the glass substrate is-20V to-210V by adopting a SIMCO ion ^TM FMX-003 electrometer, and the charging amount of the upper surface contacting air is negligible.

In order to transfer the aramid aerogel films with different charge amounts according to the needs, the invention utilizes the liquid material with good wettability with the aramid aerogel film to be compounded with the aramid aerogel film, and specifically takes the volume V _Liquid （V _Liquid to be larger than the porosity of the aerogel filmProduct of the film volume V _{Film and method for producing the same} ), impregnating the aerogel film in the liquid material of V _Liquid , fully filling the pores of the aerogel material based on proper viscosity and good wettability of the liquid material, forming a saturated liquid filling layer on the surface of the aerogel film after saturation, and molding the wet surface to form the transferable liquid confinement type aerogel film. It can be adhered to the surfaces of substrates of different materials and different shapes in a conformal manner.

Firstly, immersing an aramid aerogel film spin-coated on a glass substrate into water (the viscosity of the water is 0.89 mPa & s, the static contact angle of the water and the aramid aerogel film is 26.7 DEG), so that the water completely infiltrates the film to form a liquid confined aerogel film, then salvaging the liquid confined aerogel film by using a metal filter screen and a foam board, and as shown in figure 8a, observing that the film is flatly attached to the transferred substrate, and salvaging the film floating on the surface of the water by using regular cubes and irregular-curve desktop ornaments respectively. As shown in fig. 8b, 8c, 8d, it can be observed that the film can be transferred to the target substrate intact, perfectly fitting, whether regular or irregular. For objects of different geometric shapes, including but not limited to single plane, single curved surface, sphere, regular octahedron, penrose triangle, three-dimensional einstein Luo Senqiao, irregular object surface (such as kitten's ornament, santa Claus ornament) and the like, and for substrates of different materials (including but not limited to polymer substrate, glass substrate, stainless steel substrate, skin and the like), the transferable liquid confinement aerogel film provided by the invention can be well co-bonded.

According to the invention, poly-N-isopropyl acrylamide, hydroxypropyl cellulose, poly (N-vinyl caprolactam), eicosane, 1-octadecane, octacosane, 1-octyl-3-methylimidazole bistrifluoromethylsulfonylimine salt, 1-hydroxyethyl-3-methylimidazole bistrifluoromethylsulfonylimine salt, tetrabutylammonium 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester salt, 1-butyl-3-methylimidazole bistrifluoromethylsulfonylimide salt and dimethicone are respectively filled in the aramid aerogel film, the cellulose aerogel film prepared in the example 2 and the silica aerogel film prepared in the example 3, so that the liquid confined aerogel films filled with the liquid materials have good transferability and can be well adhered to the surfaces of substrates with various shapes and materials.

The system research shows that the viscosity of the filled liquid material and the static contact angle of the filled liquid material and the aramid aerogel film have influence on whether the liquid confined aerogel film can be well transferred and attached to the surface of a substrate in a common mode, if the viscosity of the liquid material is too high, the film is difficult to smoothly transfer, and if the static contact angle between the liquid material and the aramid aerogel film is large, functional liquid is difficult to infiltrate the film and form a saturated filling liquid layer on the surface of the film, so that the film is difficult to completely transfer and is easy to crack. When the viscosity of the liquid material is 500 mPa s or less and the static contact angle with the ultrathin aerogel film is 40 ° or less, the prepared liquid-confined aerogel film is excellent in transferability and co-lamination property.

Fig. 8e shows a photograph of a composite film filled with a liquid material having an excessively high viscosity, which is easily wrinkled and cannot be adhered to the substrate surface in a conformal manner. In addition, fig. 8e also shows a photograph of a composite film formed by unsaturated filling of a liquid material, which is found to be not completely transferred and easily broken.

Example 7

And filling positive/negative temperature-related phase-change fluid into the aramid aerogel film to prepare the transferable liquid confined aerogel film with accurately adjustable optical transparency.

Poly-N-isopropyl acrylamide (PNIPAm, positive temperature-dependent phase-change fluid) and eicosane (negative temperature-dependent phase-change fluid) are respectively filled in an aramid aerogel film (thickness 10 μm).

Fig. 9 is a graph of film transparency change during heating and cooling of a PNIPAM filled liquid confinement aerogel film. As shown in fig. 9, when the temperature was raised to 40 ℃, mona Lisa was covered with veil under the film, and when the temperature was lowered to 28 ℃, the liquid confinement aerogel film became transparent and the pattern under the film was clearly visible. FIG. 10 is a graph of film transparency change during heating and cooling of eicosane-filled liquid confinement aerogel films. As shown in fig. 10, the liquid-confinement aerogel film appeared transparent when the temperature was increased to 50 ℃, the pattern under the film was clearly visible, and Mona Lisa under the film was covered with a hazy veil when the temperature was decreased. The mechanism is that PNIPAm hydrogels exhibit clear optical properties by switching between a coil (transparent) and a sphere (opaque) at lower temperatures. The critical solution temperature (LCST) is 32 ℃, and when the temperature exceeds LCST, the polymer molecules agglomerate into spheres from a coil state, the transmittance is significantly reduced, sunlight is blocked, and the process is reversible. Eicosane provides temperature regulation during melting or crystallization by latent heat exchange. The linear hydrocarbons interact poorly, but with high symmetry, providing efficient latent heat in the most acceptable temperature range.

Example 8

A transferable liquid confinement type aerogel film with optical transparency and terahertz wave absorption performance.

50 Mu L of ionic liquid 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt is dripped on an aramid aerogel film (1.5 wt% of aramid nanofibers, the rotating speed is 4500 rpm, the volume of 3 mL of casting solution is 10 mu m), and the ionic liquid is completely infiltrated and filled in the aramid aerogel film to form a liquid confined aerogel film.

The liquid confined aerogel film is placed in a test light path of a BT-FTS5500 optical fiber coupling type terahertz spectrometer, the transmittance of the liquid confined aerogel film to terahertz wave bands is obtained, and compared with a pure aramid aerogel film and a pure glass matrix, the liquid confined aerogel film has a good absorption effect on terahertz waves, which is derived from the fact that ion pairs in 1-octyl-3-methylimidazole bis (trifluoromethylsulfonyl) imide salt generate strong ion conduction loss under terahertz wave oscillation, so that coexistence of 'light transmission' and 'strong terahertz absorption' (liquid lens) is realized, and a new path is opened up for integrated EMI shielding of an optical window. Fig. 11 is an absorption effect diagram of the liquid confinement type aerogel film in the present embodiment on terahertz waves. The liquid confined aerogel film filled with the 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide has the effects of transparency in the visible light band (the transmittance is more than 99.8%) and absorption in the terahertz band (the absorptivity is 80%).

Example 9

Mechanical tensile properties of liquid confinement type aerogel films:

50 mu L of ionic liquid 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt is dripped on an aramid aerogel film (2 wt percent of aramid nanofibers, the rotating speed is 1500 rpm, and the thickness is 57 mu m) on a glass substrate, and the ionic liquid is completely infiltrated and filled in the aramid aerogel film to form a liquid confined aerogel film.

The liquid confinement aerogel films were subjected to mechanical tensile testing, with pure aramid aerogel that was not compounded with ionic liquid as a control, and fig. 12 is a mechanical tensile stress-strain diagram of the pure aramid aerogel film and the liquid confinement aerogel film. As shown in fig. 12, the tensile strength of the aramid aerogel film itself was 0.52 MPa and the elongation at break was 8.6%, the tensile strength of the liquid-domain-limited aerogel film was increased to 0.58 MPa and the elongation at break was 10.2%, and the toughness of the liquid-domain-limited aerogel film itself was also superior to that of the solid aramid aerogel film itself in terms of the integrated area. The filling of the 1-octyl-3-methylimidazole bistrifluoromethanesulfonimide salt improves the mechanical properties of the film, so that the film can keep the integrity in the process of repeated transfer and use, and the problems of weak mechanical properties and easy breakage in the process of transfer or use of the thinner aramid aerogel film are solved.

In addition, the mechanical tensile property of the liquid confined aerogel film with the 1-hydroxyethyl-3-methylimidazole bis (trifluoromethanesulfonyl imide) salt serving as the filled liquid material is detected, and the tensile strength of the liquid confined aerogel film is 0.55 MPa and the elongation at break is 15.1%, which shows that the filling of the 1-hydroxyethyl-3-methylimidazole bis (trifluoromethanesulfonyl imide) salt can also improve the tensile property of the film.

Example 10

Flexible sensing performance of liquid confinement aerogel films:

100 mu L of ionic liquid 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt is filled in an aramid aerogel film (2 wt% of aramid nanofibers, the rotating speed is 2500 rpm, the volume of 1mL of casting solution is 19.6 mu m), and a liquid domain-limited aerogel film is formed.

The upper and lower surfaces of the liquid confinement type aerogel film are encapsulated by cured Polydimethylsiloxane (PDMS) films (132.3 mu m thick), copper conductive tapes (used as positive and negative electrodes) are adhered to the two ends of the strip-shaped sample, and the transparent solid-liquid composite sensing area between the electrodes at the two sides is 18 mm multiplied by 15 mm, so that the resistance type film sensor based on the liquid confinement type aerogel film is formed. The resistance type film sensor is repeatedly folded and deformed to obtain obvious resistance change signals, and fig. 13 shows that the resistance change rate of the resistance type film sensor is 1.5-1.7% according to the repeated folding chart and the resistance change rate of the resistance type film sensor.

Example 11

Flexible wearable sensing performance of liquid confinement aerogel films:

50 mu L of ionic liquid 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt is filled in a spin-coated aramid aerogel film (2 wt% of aramid nanofibers, the rotation speed is 2500 rpm, the volume of 1mL of casting solution and the thickness is 19.6 mu m), so that a liquid confined aerogel film is formed.

The upper and lower surfaces of the liquid confined aerogel film are encapsulated by cured Polydimethylsiloxane (PDMS) films (256.4 mu m thick), copper conductive tapes (used as positive and negative electrodes) are adhered to the two ends of the strip-shaped sample, and the transparent solid-liquid composite sensing area between the electrodes at the two sides is 12 mm multiplied by 15 mm, so that the aerogel film flexible sensor is formed. When the aerogel film flexible sensor is worn on a finger (index finger), fig. 14 is a graph showing finger straightening-bending motion sensing when the aerogel film flexible sensor is worn on the index finger in the embodiment, the aerogel film flexible sensor can be attached to a bent finger joint in a conformal manner during bending, obvious motion sensing signals are detected when repeated straightening and bending motions are carried out, the resistance change value is uniform and stable, and the highest resistance change rate can reach 4.7% under certain finger straightening and bending amplitude.

Example 12

Flexible wearable sensing performance of liquid confinement aerogel films:

Filling ionic liquid 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt into the spin-coated ultrathin aramid aerogel film to form a liquid confined aerogel film. The upper and lower surfaces of the liquid confinement aerogel film are stuck with preservative films, copper conductive tapes (used as positive and negative electrodes) are stuck at the two ends of the strip-shaped sample to form a resistance type film sensor based on the liquid confinement aerogel film, the resistance type film sensor is stuck to a wrist with gloves, the resistance change of the film is detected in real time by connecting positive and negative electrode wires of a Jili 2400 data source meter to the copper electrodes of the film sensor, and fig. 15 is a sensing performance test chart of the resistance type film sensor at the wrist in the embodiment. The result shows that the change rate of the resistance value can generate regular waveform change between 0% and 5% along with the cyclic change of the bending-straightening state of the wrist.

Example 13

Anti-contamination performance of liquid confinement aerogel films:

And placing the aramid aerogel film on a transparent glass sheet, dropwise adding 200 mu L of ionic liquid 1-octyl-3-methylimidazole bistrifluoromethane sulfonyl imide salt, instantly soaking the aramid aerogel film by using the functional liquid, and forming a saturated filling liquid layer on the surface of the aramid aerogel film to obtain the liquid confined aerogel film.

The liquid-confined aerogel film is placed in a black oil-based magnetic fluid which is not mutually soluble with ionic liquid, black oil drops are attached to the surface of the liquid-confined aerogel film, and then the liquid-confined aerogel film is taken out to be rinsed in deionized water or rinsed by flowing deionized water, and the oil drops on the surface of the liquid-confined aerogel film are rinsed away, so that no oil drops remain. Fig. 16 is a photograph of the liquid-confined aerogel film in this example immersed in a black oil-based magnetic fluid and taken out after washing. The liquid confinement aerogel film has excellent anti-pollution performance, so that the liquid confinement aerogel film can be used as a functional film layer to endow the surfaces of various materials with excellent anti-pollution and anti-scaling capabilities.

In conclusion, the liquid confined aerogel film provided by the invention can be transferred and attached to the surfaces of substrates of various materials and various shapes in a co-mode, and the substrate surface is endowed with precisely controllable optical transparency, high-efficiency terahertz wave absorption performance, excellent flexible sensing capability and excellent anti-pollution property. The liquid confined aerogel film provided by the invention has the characteristics of ultra-thin thickness, good flexibility and transferability, realizes multifunctional integration by flexibly selecting functional fluid types, is compatible with the adjustment of optical transparency and terahertz wave band absorption, has temperature-induced transparency change and pressure response behaviors, and has wide application prospects in the fields of flexible optical display, terahertz electromagnetic shielding, wearable sensing and the like.

In addition, the inventors have conducted experiments with other materials, process operations, and process conditions as described in this specification with reference to the foregoing examples, and have all obtained desirable results.

The various aspects, embodiments, features and examples of the invention are to be considered as illustrative, and not restrictive, of the invention, the scope of which is defined solely by the claims.

While the invention has been described with reference to an illustrative embodiment, it will be understood by those skilled in the art that various other changes, omissions and/or additions may be made and substantial equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.

Claims (10)

1. A transferable liquid confinement type aerogel film, characterized by comprising the following steps:

An aerogel film;

And a liquid material which is filled in the aerogel film in a saturated manner, forms a saturated filling liquid layer on the surface of the aerogel film, and has a viscosity of 500 mPa-s or less and a static contact angle with the aerogel film of 40 DEG or less.

2. The transferable liquid confinement type aerogel film of claim 1, wherein the aerogel film is an aramid aerogel film, a cellulose aerogel film, a polyimide aerogel film, or a silica aerogel film, preferably the aerogel film is an aramid aerogel film;

and/or the thickness of the aerogel film is 200 nm-300 mu m;

And/or the aperture of the aerogel film is 10 nm-50 nm, the porosity is 80% -99.5%, and the specific surface area is 200m ²/g~350 m²/g;

And/or, the mass percent of the liquid material is 70-85 wt.% of the total mass of the transferable liquid confinement aerogel film.

3. The transferable liquid confinement aerogel film of claim 1, wherein the liquid material comprises one or more of water, a phase change fluid, an ionic liquid, or silicone oil.

4. The transferable liquid confinement aerogel film of claim 3, wherein the phase-change fluid comprises a positive temperature-dependent phase-change fluid comprising one or more of poly-N-isopropylacrylamide, hydroxypropyl cellulose, poly (N-vinylcaprolactam), or a negative temperature-dependent phase-change fluid comprising one or more of eicosane, 1-octadecane, and octacosane;

and/or the ionic liquid comprises one or more of 1-octyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, 1-hydroxyethyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt, tetrabutylammonium 2-ethylhexyl phosphonate mono-2-ethylhexyl ester salt and 1-butyl-3-methylimidazole bis (trifluoromethanesulfonyl) imide salt;

And/or the silicone oil comprises one or more of dimethyl silicone oil with the viscosity of 100-500 mPas;

Preferably, the liquid material comprises 1-octyl-3-methylimidazole bistrifluoromethylsulfonylimine salt.

5. The method for preparing the transferable liquid confinement type aerogel film according to any one of claims 1 to 4, comprising:

Coating nano primitive dispersion liquid on a substrate, and sequentially carrying out sol-gel conversion, solvent replacement and drying treatment to form an aerogel film, wherein the nano primitive dispersion liquid contains nano precursor materials required for forming the aerogel film;

And (3) filling liquid materials into the porous structure of the aerogel film in a saturated manner, and forming a saturated liquid filling layer on the surface of the aerogel film, so that the transferable liquid confinement type aerogel film is obtained.

6. The preparation method of the nano-primitive dispersion liquid is characterized in that the nano-primitive dispersion liquid comprises aramid nanofibers, alkali, methanol and a solvent, wherein the concentration of the aramid nanofibers is 1-2 wt%, the mass ratio of the aramid nanofibers to the alkali is 1:0.5-1:1.5, and the mass ratio of the aramid nanofibers to the methanol is 1:0-5;

And/or coating the nano primitive dispersion liquid on a substrate by a spin coating method, wherein the spin coating speed is 500-9500 rpm, and the spin coating time is 30-90 s.

7. Use of the transferable liquid confinement aerogel film of any of claims 1-4 in flexible optical display or flexible sensing.

8. A flexible sensor comprising the transferable liquid confinement aerogel film of any one of claims 1-4.

9. Use of the transferable liquid confinement aerogel film of any of claims 1-4 in terahertz electromagnetic shielding, and the liquid material comprises an ionic liquid comprising one or more of 1-octyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, 1-hydroxyethyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, tetrabutylammonium 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester salt, 1-butyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt.

10. A terahertz wave absorbing structure comprising the transferable liquid confinement-type aerogel film of any one of claims 1-4, and the liquid material comprising an ionic liquid comprising one or more of 1-octyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, 1-hydroxyethyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt, tetrabutylammonium 2-ethylhexyl phosphonate mono-2-ethylhexyl ester salt, 1-butyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt.