A kind of intelligent textile and its preparation method and application

Abstract

The present invention provides a smart textile and a preparation method and application thereof, and relates to the technical field of smart materials. The smart textile provided by the present invention comprises a fabric and a spiropyran-conductive substrate coating attached to the surface of the fabric; the mass ratio of spiropyran to the conductive substrate in the spiropyran-conductive substrate coating is 1-40:60-99. In the present invention, neutral spiropyran (SP) molecules are converted into zwitterionic molecules with strong polarity under ultraviolet irradiation. Based on π-π conjugation, the present invention assembles spiropyran (SP) molecules with ultraviolet sensitive properties and a conductive substrate onto a fabric to prepare smart textiles with ultraviolet radiation sensing function. The SP molecules are anchored on the surface of the conductive substrate, and the conductive substrate can sense UV radiation by destroying the ‑C‑O‑covalent bonds, thereby causing the resistance of the smart textile to change, thereby achieving the purpose of monitoring ultraviolet radiation information in the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of smart materials, and in particular to a smart textile and a preparation method and application thereof. Background Art

[0002] Stimuli-responsive materials combined with textile fabrics have attracted much attention due to their sensing properties, convenient human-computer interaction, intelligent sensing of data and adaptability. In recent years, the application of smart textiles has grown rapidly, especially smart textiles that can sense environmental conditions or external stimuli (such as movement, sweetness, light, pH, temperature, pressure, mechanics, magnetic effects and electricity). It is well known that exposure to ultraviolet radiation, after accumulation, may cause sunburn, skin cancer, premature aging, and may even suppress the immune system. The use of UV sensors can help people take accurate protective measures based on the amount of UV radiation they are exposed to.

[0003] By detecting the resistance change of reduced graphene oxide (RGO) caused by electron transfer, it is helpful to monitor the change of environmental factors. Zhen et al. (Zhen, Y.; Yu, P.; Xiao-Lin, H.; Yifan, Y.; Jiang, L.; Muqiang, J.; Yingying, Z.; Yi, Y.; Tian-Ling, R., Graphene Textile Strain Sensor with Negative Resistance Variation for Human Motion Detection. ACS Nano 2018, 12, 9134-9141.) developed a graphene-based wearable textile strain sensor with different resistances through simple thermal RGO. The graphene oxide coating on the fabric acted as a colorant for polyester fabric, giving the fabric-based strain sensor excellent performance. Cao et al. (Cao, M.; Wang, M.; Li, L.; Qiu, H.; Padhiar, M. A.; Yang, Z., Wearable rGO-Ag NW@cottonFiber Piezoresistive Sensor Based on the Fast Charge Transport Channel Provided by Ag Nanowire. Nano Energy 2018, 50, 528-535.) used rGO-Ag nanowire cotton fibers to prepare a wearable flexible textile sensor. The addition of Ag nanowires provided fast electron transport, resulting in significant improvement in the performance of the textile sensor and at 0.084 kPa -1 ~4.23kPa -1It has very high sensitivity in the range. Hao Tian et al. (Shi, HTH; Jang, S.; Naguib, HE, A Freestanding Laser-Assisted Reduced Graphene Oxide Micro-Ribbon Textile Electrode Fabricated on Liquid Surfacefor Supercapacitors and Breath Sensors. ACS Appl. Mater. Interfaces 2019, 11, 27183-27191.) demonstrated a simple preparation method of RGO microstrips. This sensor prepared based on RGO microstrips can respond to changes in resistance as the moisture in human breath changes, and can be used as a respiratory sensor for health monitoring. However, the above sensor does not have ultraviolet radiation sensing function. Summary of the invention

[0004] The purpose of the present invention is to provide a smart textile and a preparation method and application thereof. The smart textile provided by the present invention has an ultraviolet radiation sensing function.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides an intelligent textile, comprising a fabric and a spiropyran-conductive substrate coating attached to the surface of the fabric; the mass ratio of spiropyran to the conductive substrate in the spiropyran-conductive substrate coating is 1-40:60-99.

[0007] Preferably, the conductive matrix comprises reduced graphene oxide or a metal material.

[0008] Preferably, the mass of the spiropyran-conductive matrix coating accounts for 0.01-1% of the mass of the smart textile.

[0009] Preferably, the fabric is cotton fabric.

[0010] The present invention provides a method for preparing the smart textile described in the above technical solution, including any one of method 1 and method 2;

[0011] Method 1: When the conductive substrate is reduced graphene oxide, spiropyran and graphene oxide powder are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; a fabric is immersed in the dispersion, the immersed fabric is taken out for padding treatment, and the fabric is reduced after drying to obtain a smart textile;

[0012] Method 2: When the conductive substrate is a metal material, spiropyran and the metal material are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; the fabric is immersed in the dispersion, the immersed fabric is taken out for a rolling treatment, and the smart textile is obtained after drying.

[0013] Preferably, the reduction treatment in the method 1 is carried out in a hydrazine hydrate solution.

[0014] Preferably, the temperature of the reduction treatment is 80-100° C.; the time of the reduction treatment is 0.5-4 h.

[0015] Preferably, the pressure of the padding treatment in the method 1 and the method 2 is independently 0.1-0.5 MPa; the speed of the padding treatment is independently 1-2 m / min.

[0016] Preferably, the concentration of the mixed powder in the dispersion of method 1 and method 2 is independently 0.1 to 0.5 wt %.

[0017] The present invention provides the use of the smart textile described in the above technical solution or the smart textile prepared by the preparation method described in the above technical solution as a textile sensor.

[0018] The present invention provides a smart textile, comprising a fabric and a spiropyran-conductive substrate coating attached to the surface of the fabric; the mass ratio of spiropyran to conductive substrate in the spiropyran-conductive substrate coating is 1-40:60-99. In the present invention, neutral spiropyran (SP) molecules are converted into zwitterionic molecules with strong polarity under ultraviolet irradiation. Based on π-π conjugation, the present invention assembles spiropyran (SP) molecules with ultraviolet sensitive properties and a conductive substrate onto a fabric to prepare a smart textile with ultraviolet radiation sensing function. The SP molecules are anchored on the surface of the conductive substrate, and the conductive substrate can sense UV radiation by destroying the -CO- covalent bond, thereby causing the resistance of the smart textile to change, thereby achieving the purpose of monitoring ultraviolet radiation information in the environment.

[0019] The results of the embodiment show that the morphology of the fabric surface coating is related to the SP content. The resistance of the smart textile decreases after UV irradiation, which is due to the easier transmission of electrons on the fabric coating. As the SP content increases, the large amount of SP in the composite material will lead to a discontinuous distribution of the conductive matrix on the fiber surface, thereby hindering the transmission of electrons in the conductive matrix. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the SEM image of the smart textile;

[0021] Figure 2is a graph showing the functional relationship between the electrical resistance of the smart textile and the SP content before and after UV radiation;

[0022] Figure 3 The variation of the UV resistance of RGO / SP-0 and RGO / SP-10 composite modified textiles with UV radiation time; Figure 3 (a) is RGO / SP-0, (b) is RGO / SP-10;

[0023] Figure 4 Schematic diagram of the changes of SP structure and RGO / SP coating based on light-driven;

[0024] Figure 5 This is a graph showing the resistance change of smart textiles before and after UV irradiation; Figure 5 (a) shows the resistance change of the smart textile after being immersed in artificial sweat and before and after being irradiated with ultraviolet light. Figure 5 (b) is a picture of the resistance of the smart textiles reduced after being soaked in artificial sweat and then irradiated with ultraviolet light, which in turn causes the brightness of the small light bulb in the circuit to change before and after ultraviolet light irradiation;

[0025] Figure 6 Comparison of wettability changes of RGO / SP-0 and RGO / SP-10 smart textiles before and after UV irradiation;

[0026] Figure 7 A schematic diagram of preparing smart textiles according to the present invention;

[0027] Figure 8 is the UV absorption spectrum of spiropyran in dark conditions;

[0028] Fig. 9 Schematic diagram of the test of smart textile resistance. DETAILED DESCRIPTION

[0029] The invention provides an intelligent textile, comprising a fabric and a spiropyran-conductive substrate coating attached to the surface of the fabric; the mass ratio of spiropyran to the conductive substrate in the spiropyran-conductive substrate coating is 1-40:60-99.

[0030] The smart textile provided by the present invention includes fabric. In the present invention, the fabric is preferably cotton fabric. In the present invention, the cotton fabric is preferably plain fabric; the specification of the cotton fabric is preferably 80g / m 2 .

[0031] The smart textile provided by the present invention comprises a spiropyran-conductive matrix coating attached to the surface of the fabric. In the present invention, the mass of the spiropyran-conductive matrix coating preferably accounts for 0.01-1% of the mass of the smart textile, and more preferably 0.05-0.2%. In the present invention, the spiropyran-conductive matrix coating comprises spiropyran and a conductive matrix. In the present invention, the spiropyran and the conductive matrix in the spiropyran-conductive matrix coating are preferably uniformly mixed.

[0032] In the present invention, the conductive substrate preferably includes reduced graphene oxide (RGO) or a metal material. In the present invention, the metal material preferably includes silver, copper, iron or aluminum. In the present invention, the size of the reduced graphene oxide is preferably 1 to 4 μm, more preferably 2 to 3 μm. In the present invention, the metal material is preferably a metal material powder, and the size is preferably 50 nm to 1 μm, more preferably 200 nm.

[0033] In the present invention, the mass ratio of the spiropyran to the conductive substrate is preferably 1:99, 10:90, 20:80, 30:70 or 40:60. In the present invention, when the conductive substrate is reduced graphene oxide, the mass of the reduced graphene oxide is calculated as the mass of graphene oxide powder.

[0034] The present invention provides a method for preparing the smart textile described in the above technical solution, including any one of method 1 and method 2;

[0035] Method 1: When the conductive substrate is reduced graphene oxide, spiropyran and graphene oxide powder are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; a fabric is immersed in the dispersion, the immersed fabric is taken out for padding treatment, and the fabric is reduced after drying to obtain a smart textile;

[0036] Method 2: When the conductive substrate is a metal material, spiropyran and the metal material are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; the fabric is immersed in the dispersion, the immersed fabric is taken out for a rolling treatment, and the smart textile is obtained after drying.

[0037] The following is a detailed description of method 1. In the present invention, when the conductive substrate is reduced graphene oxide, spiropyran and graphene oxide powder are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; a fabric is immersed in the dispersion, the immersed fabric is taken out for padding treatment, and the fabric is reduced after drying to obtain a smart textile.

[0038] The present invention grinds and mixes spiropyran and graphene oxide powder to obtain a mixed powder. In the present invention, the graphene oxide (GO) powder is preferably prepared by the Hummers method. In the present invention, the graphene oxide powder is preferably freeze-dried GO powder. In the present invention, the mass ratio of the spiropyran and graphene oxide powder is 1 to 40:60 to 99, preferably 1:99, 10:90, 20:80, 30:70 or 40:60. In the present invention, the equipment used for the grinding and mixing is preferably a planetary ball mill; the rotation speed of the grinding and mixing is preferably 600r / min; the time of the grinding and mixing is preferably 1h. In the present invention, the grinding and mixing is preferably dry grinding. The present invention makes the mixing of spiropyran and graphene oxide powder more uniform by grinding and mixing.

[0039] After obtaining the mixed powder, the present invention mixes the mixed powder with water to obtain a dispersion. In the present invention, the concentration of the mixed powder in the dispersion is preferably 0.1-0.5wt%, more preferably 0.2wt%. In the present invention, the mixing of the mixed powder and water is preferably carried out under ultrasonic conditions; the power of the ultrasound is preferably 800W; and the time of the ultrasound is preferably 1h.

[0040] After obtaining the dispersion, the present invention immerses the fabric in the dispersion, takes out the immersed fabric for padding treatment, and performs reduction treatment after drying to obtain smart textiles. In the present invention, the fabric preferably also includes pretreatment before the impregnation. In the present invention, the pretreatment method of the fabric preferably includes: ultrasonic cleaning and drying the fabric in sequence. In the present invention, the ultrasonic cleaning preferably includes deionized water ultrasonic cleaning, acetone ultrasonic cleaning and ethanol ultrasonic cleaning in sequence. In the present invention, the time for the deionized water ultrasonic cleaning, acetone ultrasonic cleaning and ethanol ultrasonic cleaning is preferably 30 minutes.

[0041] In the present invention, the immersion temperature is preferably room temperature; the immersion time is preferably 10 minutes.

[0042] In the present invention, the pressure of the padding treatment is preferably 0.1-0.5 MPa, more preferably 0.2 MPa; the speed of the padding treatment is preferably 1-2 m / min, more preferably 1.5 m / min. In the present invention, the padding treatment is preferably carried out in a two-roll padder. In the present invention, the number of padding treatments is preferably 5 times. In the present invention, the drying temperature is preferably 60°C; the drying time is preferably 30 min.

[0043] In the present invention, the reduction treatment is preferably carried out in a hydrazine hydrate solution. In the present invention, the mass concentration of the hydrazine hydrate solution is preferably 85%.

[0044] In the present invention, the temperature of the reduction treatment is preferably 80-100° C., more preferably 90° C.; the time of the reduction treatment is preferably 0.5-4 h, more preferably 3 h.

[0045] In the present invention, after the reduction treatment, the obtained fabric is preferably washed and dried in sequence to obtain the smart textile. In the present invention, the washing is preferably done with deionized water; and the drying temperature is preferably 60°C.

[0046] The second method is described in detail below. When the conductive substrate is a metal material, spiropyran and the metal material are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; a fabric is immersed in the dispersion, the immersed fabric is taken out for padding treatment, and the smart textile is obtained after drying.

[0047] The present invention grinds and mixes spiropyran and metal material to obtain mixed powder. In the present invention, the mass ratio of the spiropyran and the metal material is 1 to 40:60 to 99, preferably 1:99, 10:90, 20:80, 30:70 or 40:60. In the present invention, the equipment used for the grinding and mixing is preferably a planetary ball mill; the rotation speed of the grinding and mixing is preferably 600r / min; the time of the grinding and mixing is preferably 1h. In the present invention, the grinding and mixing is preferably dry grinding. The present invention makes the mixing of spiropyran and metal material more uniform through grinding and mixing.

[0048] After obtaining the mixed powder, the present invention mixes the mixed powder with water to obtain a dispersion. In the present invention, the concentration of the mixed powder in the dispersion is preferably 0.1-0.5wt%, more preferably 0.2wt%. In the present invention, the mixing of the mixed powder and water is preferably carried out under ultrasonic conditions; the power of the ultrasound is preferably 800W; and the time of the ultrasound is preferably 1h.

[0049] After obtaining the dispersion, the present invention immerses the fabric in the dispersion, takes out the immersed fabric for padding treatment, and obtains the smart textile after drying. In the present invention, the fabric preferably also includes pretreatment before the impregnation. In the present invention, the pretreatment method of the fabric preferably includes: ultrasonic cleaning and drying the fabric in sequence. In the present invention, the ultrasonic cleaning preferably includes deionized water ultrasonic cleaning, acetone ultrasonic cleaning and ethanol ultrasonic cleaning in sequence. In the present invention, the time of the deionized water ultrasonic cleaning, acetone ultrasonic cleaning and ethanol ultrasonic cleaning is preferably 30 minutes.

[0050] In the present invention, the immersion temperature is preferably room temperature; the immersion time is preferably 10 minutes.

[0051] In the present invention, the pressure of the padding treatment is preferably 0.1-0.5 MPa, more preferably 0.2 MPa; the speed of the padding treatment is preferably 1-2 m / min, more preferably 1.5 m / min. In the present invention, the padding treatment is preferably carried out in a two-roll padder. In the present invention, the number of padding treatments is preferably 5 times. In the present invention, the drying temperature is preferably 60°C; the drying time is preferably 30 min.

[0052] The present invention provides the use of the smart textile described in the above technical solution or the smart textile prepared by the preparation method described in the above technical solution as a textile sensor, preferably as a photosensitive or sweat-sensitive textile sensor.

[0053] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Experimental Materials

[0055] Cotton fabric (plain weave, 80g / m 2 ) was purchased from Huafang Co., Ltd. and ultrasonically cleaned with deionized water, acetone and ethanol for 30 min respectively, and then dried.

[0056] Spiropyran (SP) was sourced from TCI (Shanghai) Development Co., Ltd.

[0057] Hydrazine hydrate solution (concentration 85 wt%), H2SO4 (98.0%), NaNO3 (≥99.0%), H2O2 (≥30.0%), KMnO4 (≥99.5%) and graphite powder (≥99.85%) were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0058] All chemical reagents were used as received without purification.

[0059] The water used in the experiment was filtered and purified, and the resistivity was 18.2MΩ·cm.

[0060] Graphene oxide (GO) was prepared by Hummers method.

[0061] Examples and Comparative Examples

[0062] SP was mixed with freeze-dried GO powder and ground for 1 h at a grinding speed of 600 r / min to obtain a mixed powder; the mass ratios of SP and freeze-dried GO powder were 0:100 (comparative example), 1:99, 10:90, 20:80, 30:70, and 40:60, respectively;

[0063] The mixed powders were mixed with water to prepare a dispersion with a concentration of 0.2 wt %, and dispersed by ultrasound (power of 800 W) for 1 h;

[0064] Six pieces of cotton fabrics of 5 cm × 10 cm were placed in the above dispersions of different compositions, immersed at room temperature for 10 min, and then padded by a two-roll padding machine in the laboratory at a pressure of 0.2 MPa and a speed of 1.5 m / min; the above padding process was repeated 5 times and dried at 60°C;

[0065] The obtained cotton fabric was then reduced in a hydrazine hydrate solution at 90 °C for 3 h, washed with deionized water, and dried at 60 °C to obtain smart textiles, which were labeled as RGO / SP@CF-0 (corresponding to the mass ratio of SP and freeze-dried GO powder of 0:100), RGO / SP@CF-1 (corresponding to the mass ratio of SP and freeze-dried GO powder of 1:99), RGO / SP@CF-10 (corresponding to the mass ratio of SP and freeze-dried GO powder of 10:90), RGO / SP@CF-20 (corresponding to the mass ratio of SP and freeze-dried GO powder of 20:80), RGO / SP@CF-30 (corresponding to the mass ratio of SP and freeze-dried GO powder of 30:70), and RGO / SP@CF-40 (corresponding to the mass ratio of SP and freeze-dried GO powder of 40:60).

[0066] The smart textile consists of a cotton fabric and an RGO / SP coating attached to the surface of the cotton fabric, and the RGO / SP coatings are respectively marked as RGO / SP-0 (corresponding to a mass ratio of SP to freeze-dried GO powder of 0:100), RGO / SP-1 (corresponding to a mass ratio of SP to freeze-dried GO powder of 1:99), RGO / SP-10 (corresponding to a mass ratio of SP to freeze-dried GO powder of 10:90), RGO / SP-20 (corresponding to a mass ratio of SP to freeze-dried GO powder of 20:80), RGO / SP-30 (corresponding to a mass ratio of SP to freeze-dried GO powder of 30:70) and RGO / SP-40 (corresponding to a mass ratio of SP to freeze-dried GO powder of 40:60).

[0067] Test Case

[0068] The surface morphology of cotton fabrics was observed using a Quanta400F scanning electron microscope (SEM).

[0069] The UV absorption spectrum of spiropyran in dark conditions is shown in Figure 8 , the present invention adopts 365nm for testing.

[0070] The resistance of smart textiles is Fig. 9 The method shown was tested.

[0071] The water contact angle of the cotton fabric surface was measured at 25°C using a contact angle goniometer (Krüss, Drop Shape Analyzer series).

[0072] (1) Morphology of smart textiles

[0073] Figure 1 The surface morphology of smart textiles before and after modification. Figure 1 a is CF (cotton fabric), b is RGO / SP@CF-0, c is RGO / SP@CF-10, d is RGO / SP@CF-20, e is RGO / SP@CF-30, and f is RGO / SP@CF-40. Scanning electron microscope image analysis shows that some pollutant particles are attached to the original, unmodified cotton fiber surface, indicating that the cotton fabric surface is not completely smooth. After a certain concentration of reduced graphene oxide modification ( Figure 1 b), the cotton fiber surface is covered with a layer of disordered reduced graphene oxide. The surface coating layer of some modified fibers is arranged in an orderly manner, but due to the agglomeration and hardening of RGO, defects and protrusions appear in some parts ( Figure 1 b). Due to the electrostatic repulsion, the carboxyl groups of graphene oxide make the graphene oxide uniformly dispersed in water, while graphene oxide presents disordered morphology stacking on the cotton fiber surface during the impregnation filling process, which may be caused by different numbers of graphene oxide carboxyl groups due to the electrostatic repulsion.

[0074] exist Figure 1 In Figure c, as the content of SP in the composite material increases from 0 to 10%, the coating RGO / SP layer on the fiber surface becomes orderly and uniform. This is because when the SP molecules are adsorbed onto the graphene oxide surface through the π-π interaction between graphene oxide and SP molecules, the graphene oxide is stacked on the cotton fiber surface in an orderly state, thereby forming an orderly distribution on the fiber surface at the macroscopic level. When the SP molecules are introduced onto the graphene oxide surface, the hydrophobicity of the SP and the hydrophobic part of the graphene oxide reduces the mutual repulsion, thereby causing the π-π interaction between SP and graphene oxide, and the SP molecules are fixed on the graphene oxide surface. The hydrophobicity reduces the solubility of graphene oxide in water, thereby achieving the orderly induced assembly of the coating, so that the composite material can be orderly covered instead of randomly stacked on the cotton fiber surface. Therefore, the coating on the cotton fiber has good uniformity.

[0075] The introduction of a large amount of SP in the composite material will lead to the protrusion and wrinkle structure on the surface of RGO fibers ( Figure 1 However, when the proportion of SP increases to a certain extent, the composite coating begins to show a small amount of unevenness on the cotton fiber surface ( Figure 1d). When the SP content in the composite material increases from 30% to 40%, the wrinkled structure on the cotton fiber surface can be observed. This may be due to the aggregation of the RGO / SP composite material and the SP molecules themselves when the SP content is high, which leads to the wrinkled structure on the cotton fiber surface ( Figure 1 E and Figure 1 f). In addition, the presence of SP hinders the transmission of electrons in the reduced graphene oxide of the composite coating, which makes the composite coating respond to ultraviolet radiation.

[0076] (2) UV response characteristics of smart textiles

[0077] Photochromic dyes, which undergo photoinduced transformations by changing their structure to absorb radiation stimulated by light, can be used to adjust the electrical resistance of cotton fabrics. Figure 2 Among them, the resistance of cotton fabrics of RGO / SP@CF-1, RGO / SP@CF-20, RGO / SP@CF-30, and RGO / SP@CF-40 is relatively small, while the resistance of RGO / SP@CF-10 changes significantly compared with other SP contents. Figure 1 As shown in the figure, the surface morphology of cotton fabric coated with RGO / SP-10 is regular, and the reduced graphene oxide is stacked into a thick layered structure, indicating that the regular coating may change the electron transmittance before and after UV irradiation. When the SP content is low (1%), the change of the SP structure inside the coating is not enough to change the arrangement of reduced graphene oxide. When the SP content increases to 20%, 30%, and 40%, the high SP content disturbs the continuity of reduced graphene oxide, resulting in a decrease in the resistance sensitivity on cotton fabric.

[0078] (3) Changes in resistance of smart textiles with UV radiation time

[0079] like Figure 2 The figure shows the resistance change of cotton fiber modified by RGO / SP composite under UV radiation. In addition, it is necessary to detect how the resistance of smart textiles is a function of UV radiation time, because in some realistic cases, UV radiation can last for a long time. Figure 3In the results, the resistance of RGO / SP-0 modified cotton fibers remained almost constant over time, while the resistance of RGO / SP-10 composite coated cotton fibers decreased with increasing UV irradiation time. The stacking structure of RGO / SP-0 is insensitive to UV rays, and therefore, the RGO / SP-0 coating is also unaffected by UV radiation, which results in unchanged resistance of cotton fibers during UV irradiation. However, when the covalent bond between the carbon and oxygen atoms within the SP molecule breaks, the configuration of the SP molecule changes, leading to the formation of ion pairs under UV light. As the UV irradiation time increases, the number of ion pairs increases until the breakage and recombination of the -CO covalent bond reaches a steady-state equilibrium stage, which contributes to the strong interaction between the RGO / SP-10 composites. Therefore, the denser coating structure on the cotton fiber is conducive to the directional transmission of electrons on the textile surface.

[0080] SP dye molecules are known for their good photochromic properties and reversible transformation under UV-visible radiation. Figure 2 and Figure 3 As shown in Figure 2, the breaking of the -CO covalent bond leads to a change in the resistance of the smart textile under UV radiation. That is, compared with the original SP molecule, the molecular configuration and polarity have changed ( Figure 4 ). Therefore, the -N + The -O group is generated after the -CO covalent bond is broken. Therefore, the dipole-dipole interaction between different ion pairs tightens the distance between the two sheets of reduced graphene oxide. At the same time, the -N + The -O in another SP molecule will be attracted, which will also cause the spacing of the reduced graphene oxide sheets to become smaller, resulting in a decrease in the resistance of the cotton fabric. The change in resistance of smart textiles under UV irradiation can be used as a new type of environmental UV recording method.

[0081] (4) Analysis of artificial sweat reaction and wetting properties

[0082] When the ions in sweat interact with the -N + and -O - The groups interact specifically when they come into contact, so the effect of sweat on the resistance change of smart textiles was studied. + and -O - The groups interact specifically with each other. Some ions in sweat can bind tightly to them, reducing their movement rate, while some ions form relatively loose ions, making it easier for them to move. Under ultraviolet light, the newly generated -N + and -O -The groups increase the polarity of the textile sensor surface, enhance the ability to bind ions, and promote the formation of more ion channels. Therefore, the resistance of the textile sensor is determined by the interaction between different ions in sweat and -N + and -O - The ion pairs formed by the groups and the electron transport within the RGO nanosheets are jointly determined.

[0083] like Figure 5 As shown in the figure, after RGO / SP@CF-10 was immersed in artificial sweat with pH values ​​of 4.5 and 8.0 and then irradiated with ultraviolet light, -N + and -O - The polarity of the textile sensor increases, making the movement of ions easier and reducing the resistance of the textile sensor. The ions in artificial sweat further reduce the cationic-N + and anion-O - Electrostatic attraction between groups. Different interactions inside the textile sensor form more ion channels within the RGO layer spacing, which reduces the resistance of the textile sensor. Therefore, this new type of photosensitive textile can be used in light-sensitive and sweat-sensitive textile sensors. Figure 5 (a) shows the resistance change of the textile sensor after being immersed in artificial sweat and before and after being irradiated with ultraviolet light. It can be seen that the resistance value has been significantly reduced. Figure 5 (b) shows a RGO / SP@CF-10 textile sensor soaked in artificial sweat with a pH value of 4.5 connected in series in the small bulb circuit. After the circuit is closed, the brightness of the small bulb is low. After the textile sensor is irradiated with ultraviolet light, its resistance decreases and the brightness of the small bulb is significantly improved.

[0084] (5) Wettability of smart textiles before and after UV radiation

[0085] Direct observation of wettability changes can provide insight into the intensity of UV radiation. Figure 6 In the experiment, the wettability of the RGO / SP-0 textile sensor remained unchanged, while the wettability of the RGO / SP-10 coating on the textile sensor decreased under UV irradiation. As mentioned above, the structure and polarity of the RGO / SP-0 coating did not change under UV irradiation, and the contact angle before and after UV irradiation was a constant value. For the RGO / SP-10 coating, since the SP molecules are neutral before UV irradiation, the coating with lower polarity has a weaker interaction with water, resulting in a larger contact angle. Under the action of UV radiation and water, N + The interaction of the O and O groups with the SP molecules in the fabric coating increased, resulting in a decrease in the contact angle, indicating that the wettability of the textile sensor increased under UV irradiation. As the SP content increased, the contact angle between the coating and the fabric increased ( Figure 6 ). Figure 1It shows that as the SP content increases, the roughness of the coating increases, the polarity of the coating increases, and the contact angle should decrease. Figure 6 In the figure, the contact angle of RGO / SP-10 coating is larger than that of RGO / SP-0 coating, indicating that the roughness of the coating plays a dominant role in the wettability of the textile sensor.

[0086] The present invention adopts the dipping-rolling method and the chemical reduction method to prepare the RGO / SP coating with photosensitivity and ion sensing functions. The RGO / SP-0 coating prepared on the fabric has no reaction to ultraviolet light and various solutions, while the RGO / SP-10 coating has a good reaction to ultraviolet light and different sweat solutions, which is due to the breakage of the -CO covalent bond under ultraviolet light. In the case of low SP content, the ultraviolet radiation caused by the low SP content in the composite material makes the resistance of the textile sensor basically unchanged, and SP does not affect the resistance performance of the textile sensor. The RGO / SP-10 coating has obvious resistance performance before and after ultraviolet radiation and can be used as a photosensitive textile sensor. The fabric-based ultraviolet sensor also shows different artificial sweat responses and wettability under ultraviolet radiation. The resistance of the textile under ultraviolet light irradiation is reduced, which may be due to the formation of more ion channels within the interlamellar spacing of the RGO. Under ultraviolet light irradiation, the contact angle of the RGO / SP-10 coating on the textile sensor decreases due to the increase in polarity. This work provides a certain reference for the action mechanism of RGO / SP in optical sensing and provides ideas for the design of the next generation of highly sensitive smart ion sensors.

[0087] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a smart textile, characterized in that: The method comprises any one of method 1 and method 2; the smart textile comprises a fabric and a spiropyran-conductive substrate coating attached to the surface of the fabric; the mass ratio of spiropyran to the conductive substrate in the spiropyran-conductive substrate coating is 1-40:60-99; Method 1: When the conductive substrate is reduced graphene oxide, spiropyran and graphene oxide powder are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; a fabric is immersed in the dispersion, the immersed fabric is taken out for padding treatment, and the fabric is reduced after drying to obtain a smart textile; Method 2: When the conductive substrate is a metal material, spiropyran and the metal material are ground and mixed to obtain a mixed powder; the mixed powder is mixed with water to obtain a dispersion; the fabric is immersed in the dispersion, the immersed fabric is taken out for a rolling treatment, and the smart textile is obtained after drying.

2. The preparation method according to claim 1, characterized in that: In the method 1, the reduction treatment is carried out in a hydrazine hydrate solution.

3. The preparation method according to claim 2, characterized in that: The temperature of the reduction treatment is 80-100° C.; the time of the reduction treatment is 0.5-4 hours.

4. The preparation method according to claim 1, characterized in that: The pressure of the padding treatment in the method 1 and the method 2 is independently 0.1-0.5 MPa; the speed of the padding treatment is independently 1-2 m / min.

5. The preparation method according to claim 1, characterized in that: The concentration of the mixed powder in the dispersion of method 1 and method 2 is independently 0.1 to 0.5 wt %.

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