阅读说明：本技术 一种具有电流变效应的电泳液及其制备方法 (Electrophoresis liquid with electrorheological effect and preparation method thereof ) 是由 吴梓荣 李捷妮 陈嵘 于 2019-10-23 设计创作，主要内容包括：本发明所述的电泳粒子的电流变效应为逆流电变液原理,所谓逆电流变液是指在电泳液体系中加入的具有电流变效应的材料在非导电状态时,所加入的电流变材料具有彼此之间相互通过物理交联形成网络结构的能力,形成非牛顿流体,导电状态时,电场作用电泳粒子冲击交联的网络结构而断开形成牛顿流体,粒子的运动速度随着电泳液体系粘度降低而运动速度倍速增长。电泳粒子剪切强度高,通过该方法节省了多种原材料的成本,在保证电子纸的响应时间的情况下也保证能达到双稳态效应。(The electrorheological effect of the electrophoretic particles is a reverse electrorheological fluid principle, the reverse electrorheological fluid refers to that when materials with electrorheological effect added into an electrophoretic liquid system are in a non-conductive state, the added electrorheological materials have the capacity of forming a network structure through mutual physical crosslinking, so that a non-Newtonian fluid is formed, when the materials are in a conductive state, an electric field acts on the electrophoretic particles to impact the crosslinked network structure to break the crosslinked network structure so as to form a Newtonian fluid, and the movement speed of the particles is increased by times along with the reduction of the viscosity of the electrophoretic liquid system. The electrophoretic particles have high shearing strength, the cost of various raw materials is saved by the method, and the bistable effect can be ensured under the condition of ensuring the response time of the electronic paper.)

1. An electrophoresis liquid with electrorheological effect is characterized in that: the electrophoresis liquid comprises electrophoresis particles, a solvent, a charge control agent, a stabilizer and at least one material with electrorheological effect, wherein in the electrophoresis liquid with electrorheological effect, the mass of the solvent accounts for 30-80% of the system, the mass of the electrophoresis particles accounts for 17-65% of the system, and the mass of the material with electrorheological effect, the charge control agent and the stabilizer accounts for 3-5% of the system.

2. The electro-rheological fluid of claim 1, wherein: the electrophoretic particles comprise a base material comprising one of the following compounds: TiO 2₂、Al₂O₃、BaSO₄、Fe₂O₃、SiO₂Carbon black, cobalt green, copper chromium black, calcium carbonate, organic red, organic blue, organic green or organic yellow, wherein the electrophoretic particles are prepared by the following steps:

s1, dispersing a base material in a first solvent, wherein the mass of the base material accounts for 2-60% of that of the first solvent, dispersing for 10-120min under the conditions of heating and stirring, then adding a second solvent and a modifier under the acidic or alkaline condition, and stirring for 30-500min to obtain a first reaction product;

s2, removing the solvent from the first reaction product, cleaning the first reaction product by using a third solvent, and dispersing the cleaned first reaction product into the third solvent, wherein the mass of the first reaction product is 20-80% of that of the third solvent, so as to obtain a second reaction product;

s3, placing the second reaction product under the conditions of sealing and oxygen resisting to perform rotary stirring at the rotating speed of 200-1000 rpm, and adding an organic monomer with at least one of the following groups: -CH2CH2-, -COOH, C-NH2, N-O, C-O, N-H, F-H, C-OH, C-NO2 or C-Cl; dissolving an initiator in the third solvent to obtain an initiator mixed solution, wherein the mass of the initiator is 3-10% of that of the third solvent, dropwise adding the initiator mixed solution under the condition that the heating temperature is 30-130 ℃, the dropwise adding time of the initiator mixed solution is 1-500min, and reacting for 5-130h after the dropwise adding is finished to obtain a third reaction product;

s4, cleaning the third reaction product by using the third solvent, then cleaning by using a fourth solvent, and obtaining a fourth reaction product after cleaning is finished; and dispersing the fourth reaction product in the fourth solvent to obtain electrophoretic particles, wherein the mass of the fourth reaction product is 5-60% of that of the fourth solvent.

3. The electro-rheological fluid of claim 2, wherein:

the first solvent is one of water, ethanol, methanol, n-butanol, toluene, xylene, dichloromethane and tetrachloroethylene;

the second solvent is one of water, ethanol, methanol, n-butanol, toluene, xylene, dichloromethane and tetrachloroethylene;

the third solvent is one of water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, an alkane solvent or an isoparaffin solvent;

the fourth solvent is one of water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, an alkane solvent, an isoparaffin solvent, simethicone, vinyl silicone oil or castor oil.

4. The electro-rheological fluid of claim 2, wherein: in the step S1, the modifier is a titanate coupling agent, an aluminate coupling agent, a silane coupling agent, a surfactant or an initiator; wherein:

the titanate coupling agents are: isopropyl trioleate titanate, isopropyl triisostearate titanate, diisopropyl di (acetylacetonate) titanate, isopropyl dioleate acyloxy (dioctylphosphonoyl) titanate or isopropyl tri (dioctylphosphonoyl) titanate;

the aluminate coupling agent is: isopropoxydistearoyloxyaluminate;

the silane coupling agents are: 3- (2-aminoethyl) -aminopropyltriethoxysilane, 2- (3, 4-epoxycyclopolyethyl) ethyldimethylsilane, 3- (N, N-dimethylaminopropyl) -aminopropylmethyldimethoxysilane, r-glycidyloxypropyltriethoxysilane, r-methacryloyloxytrimethoxysilane or r-glycidyloxypropyltrimethoxysilane;

the initiator is as follows: dibenzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, potassium persulfate, ammonium persulfate, or dimethyl azobisisobutyrate.

5. The electro-rheological fluid of claim 2, wherein: in step S3, the organic monomers are: at least one of methyl methacrylate, aniline, o-toluidine, lauryl methacrylate, octadecyl methacrylate, vinyl silicone oil and styrene; the initiator is at least one of dibenzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, potassium persulfate, ammonium persulfate and dimethyl azobisisobutyrate.

6. The electro-rheological fluid of claim 1, wherein:

the solvent is one of pure water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, alkane solvent or isoparaffin solvent, silicone oil, vegetable oil and castor oil;

the stabilizer is polyvinylpyrrolidone.

7. The electro-rheological fluid of claim 1, wherein: the material with electrorheological effect is at least one of inorganic nano-particles or high molecular oligomers such as hydrogenated castor oil, glycerol, polyamide wax powder, superfine kaolin, superfine silicon dioxide, polyisobutylene and the like;

the material with the electrorheological effect is a positive electrorheological material or a reverse electrorheological material;

the material with electrorheological effect comprises a long-chain, oleophilic organic segment and a short-chain functional segment, wherein the short-chain functional segment comprises at least one of-COO-, -NHCO-, -SO2 Cl-CH 2CH 2-.

8. The electrorheological fluid according to claim 1 wherein the charge control agent is at least one of a cationic surfactant, an anionic surfactant, a nonionic surfactant, or a zwitterionic surfactant;

the cationic surfactant is: octadecyl trimethyl ammonium chloride or N, N dimethyl dodecyl amine;

the anionic surfactant is: sodium dodecylbenzene sulfonate or sodium ethoxyethyl sulfate;

the nonionic surfactant is as follows: alkyl alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether;

the zwitterionic surfactant is as follows: ethoxylated nonylphenol sulfosuccinic acid half ester disodium salt or dodecyl dimethyl betaine.

9. An electro-rheological fluid having an electro-rheological effect as claimed in any one of claims 1-8 wherein: the electrophoresis liquid contains at least one electrophoresis particle.

Technical Field

The invention relates to the field of electrophoretic display, in particular to an electrophoretic fluid with electrorheological effect and a preparation method thereof.

Background

Electronic paper is increasingly popular in the market as a light, thin and flexible display device, and in recent years, electronic paper has come into the consumer electronics field, and has been widely applied to billboards and price display boards. The electrophoretic particles are the core of electrophoretic display, and have good effects of protecting eyes, reducing energy consumption, protecting environment and the like through a light-source-free turnover display mode.

The display bistable state is a key technology of the electronic paper, and the characteristic of electrophoretic particles settling due to gravity needs to be overcome to achieve the bistable state, so that the shape stability and the dispersion stability of the electrophoretic particles in an electrophoretic solution are maintained, and the display state is kept for a longer time. The electrophoretic fluid can be made into a slurry type, the viscosity of the electrophoretic fluid system is increased to slow down the sedimentation velocity of electrophoretic particles, or polyisoprene is added into the electrophoretic fluid to improve the bistable state. The electrophoretic particles of the prior art often do not disperse stably in the flowing liquid, resulting in the occurrence of aggregates. When the electrophoretic particles are dispersed in a flowing liquid for a long time, the electrophoretic particles change their own properties, which increases the response time of the electronic paper and decreases the contrast. Meanwhile, the material cost for producing the electrophoretic particles and the electrophoretic liquid in the prior art is higher.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the electrophoretic fluid with electrorheological effect has lower production cost and better bistable effect and the preparation method thereof.

In order to solve the above technical problem, the present invention provides an electrophoretic fluid with an electrorheological effect, which is characterized in that: the electrophoresis liquid comprises electrophoresis particles, a solvent, a charge control agent, a stabilizer and at least one material with electrorheological effect, wherein in the electrophoresis liquid with electrorheological effect, the mass of the solvent accounts for 30-80% of the system, the mass of the electrophoresis particles accounts for 17-65% of the system, and the mass of the material with electrorheological effect, the charge control agent and the stabilizer accounts for 3-5% of the system.

Further, the electrophoretic particles comprise a base material comprising one of the following compounds: TiO 2₂、Al₂O₃、BaSO₄、Fe₂O₃、SiO₂Carbon black, cobalt green, copper chromium black, calcium carbonate, organic red, organic blue, organic green or organic yellow, wherein the electrophoretic particles are prepared by the following steps:

s1, dispersing a base material in a first solvent, wherein the mass of the base material accounts for 2-60% of that of the first solvent, dispersing for 10-120min under the conditions of heating and stirring, then adding a second solvent and a modifier under the acidic or alkaline condition, and stirring for 30-500min to obtain a first reaction product;

s2, removing the solvent from the first reaction product, cleaning the first reaction product by using a third solvent, and dispersing the cleaned first reaction product into the third solvent, wherein the mass of the first reaction product is 20-80% of that of the third solvent, so as to obtain a second reaction product;

s3, placing the second reaction product under the conditions of sealing and oxygen resisting to perform rotary stirring at the rotating speed of 200-1000 rpm, and adding an organic monomer with at least one of the following groups: -CH2CH2-, -COOH, C-NH2, N-O, C-O, N-H, F-H, C-OH, C-NO2 or C-Cl; dissolving an initiator in the third solvent to obtain an initiator mixed solution, wherein the mass of the initiator is 3-10% of that of the third solvent, dropwise adding the initiator mixed solution under the condition that the heating temperature is 30-130 ℃, the dropwise adding time of the initiator mixed solution is 1-500min, and reacting for 5-130h after the dropwise adding is finished to obtain a third reaction product;

s4, cleaning the third reaction product by using the third solvent, then cleaning by using a fourth solvent, and obtaining a fourth reaction product after cleaning is finished; and dispersing the fourth reaction product in the fourth solvent to obtain electrophoretic particles, wherein the mass of the fourth reaction product is 5-60% of that of the fourth solvent.

Further, the first solvent is one of water, ethanol, methanol, n-butanol, toluene, xylene, dichloromethane and tetrachloroethylene;

the second solvent is one of water, ethanol, methanol, n-butanol, toluene, xylene, dichloromethane and tetrachloroethylene;

the third solvent is one of water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, an alkane solvent or an isoparaffin solvent;

the fourth solvent is one of water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, an alkane solvent, an isoparaffin solvent, simethicone, vinyl silicone oil or castor oil.

Further, in the step S1, the modifier is a titanate coupling agent, an aluminate coupling agent, a silane coupling agent, a surfactant, or an initiator; wherein:

the titanate coupling agents are: isopropyl trioleate titanate, isopropyl triisostearate titanate, diisopropyl di (acetylacetonate) titanate, isopropyl dioleate acyloxy (dioctylphosphonoyl) titanate or isopropyl tri (dioctylphosphonoyl) titanate;

the aluminate coupling agent is: isopropoxydistearoyloxyaluminate;

the silane coupling agents are: 3- (2-aminoethyl) -aminopropyltriethoxysilane, 2- (3, 4-epoxycyclopolyethyl) ethyldimethylsilane, 3- (N, N-dimethylaminopropyl) -aminopropylmethyldimethoxysilane, r-glycidyloxypropyltriethoxysilane, r-methacryloyloxytrimethoxysilane or r-glycidyloxypropyltrimethoxysilane;

the initiator is as follows: dibenzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, potassium persulfate, ammonium persulfate, or dimethyl azobisisobutyrate.

Further, in step S3, the organic monomers are: at least one of methyl methacrylate, aniline, o-toluidine, lauryl methacrylate, octadecyl methacrylate, vinyl silicone oil and styrene; the initiator is at least one of dibenzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, potassium persulfate, ammonium persulfate and dimethyl azobisisobutyrate.

Further, the solvent is one of pure water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, alkane solvent or isoparaffin solvent, silicone oil, vegetable oil and castor oil;

the stabilizer is polyvinylpyrrolidone.

Further, the material with electrorheological effect is at least one of inorganic nano-particles or high molecular oligomers such as hydrogenated castor oil, glycerol, polyamide wax powder, superfine kaolin, superfine silicon dioxide, polyisobutylene and the like;

the material with the electrorheological effect is a positive electrorheological material or a reverse electrorheological material;

the material with electrorheological effect comprises a long-chain, oleophilic organic segment and a short-chain functional segment, wherein the short-chain functional segment comprises at least one of-COO-, -NHCO-, -SO2 Cl-CH 2CH 2-.

Further, the charge control agent is at least one of cationic surfactant, anionic surfactant, nonionic surfactant or zwitterionic surfactant;

the cationic surfactant is: octadecyl trimethyl ammonium chloride or N, N dimethyl dodecyl amine;

the anionic surfactant is: sodium dodecylbenzene sulfonate or sodium ethoxyethyl sulfate;

the nonionic surfactant is as follows: alkyl alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether;

the zwitterionic surfactant is as follows: ethoxylated nonylphenol sulfosuccinic acid half ester disodium salt or dodecyl dimethyl betaine.

Furthermore, the electrophoresis particles in the electrophoresis liquid with electrorheological effect are at least one.

The invention has the beneficial effects that: the electrorheological effect of the electrophoretic particles is the electroviscosity and the double electric layer effect, the electroviscosity is that the electrophoretic particles form a bonding layer through the transfer between organic matter charges coated on the surface, the viscosity of the electrophoretic particles is increased by multiple orders or even orders of magnitude, the shearing strength of the electrophoretic particles is high, the method saves the cost of various raw materials, and the bistable effect can be ensured under the condition of ensuring the response time of electronic paper.

Drawings

The invention is described in detail below with reference to the accompanying drawings:

FIG. 1 is a white L-value comparison chart according to an embodiment of the present invention;

FIG. 2 is a graph comparing black L values in the examples of the present invention.

Detailed Description

In order to make the objects, technical solutions and technical effects of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and the specific embodiments, it should be understood that the specific embodiments described in the present specification are only for explaining the present invention and are not intended to limit the present invention.

The invention provides an electrophoretic fluid with electrorheological effect. At least one material with electrorheological effect is added into the electrophoretic liquid, and the material has long-chain, oleophilic organic segment and short-chain functional segment and plays a role in physical connection or chemical connection in an electrophoretic liquid system. In the electrophoresis liquid system, the mass of the solvent accounts for 30-80% of the system, the mass of the electrophoresis particles accounts for 17-65% of the system, and the mass of the material with electrorheological effect, the charge control agent and the stabilizing agent accounts for 3-5% of the system.

Specifically, the electrophoretic particles are inorganic materials, organic materials or composite materials; the electrophoretic particles comprise at least one of the following elements: al, C, Si, Ti, O, Cu, Fe, Ba, Mo, Cr, F, Ca, Co, S, N, H or Cl. In this embodiment, the electrophoretic particles include one of the following compounds: TiO prepared by tetrabutyl titanate sol-gel process₂Commercial TiO 2₂、Al₂O₃、BaSO₄、Fe₂O₃、 SiO₂Carbon black, cobalt green, copper chromium black, calcium carbonate, organic red, organic blue, organic green or organic yellow, and the surface of the particles is organically modified to increase the steric hindrance of the particles in the electrophoretic solution.

Specifically, the material with electrorheological effect is an organic polymer with long framework, or a mixture of polymer and particles, and the connection or disconnection can be performed through a physical or chemical method, so that the electrophoretic fluid can be freely and reversibly switched between the non-newtonian fluid and the newtonian fluid. When the electrophoretic liquid is converted into the Newtonian fluid, the electrophoretic particles can freely move in the electrophoretic liquid under the action of the electric field to realize the conversion of the display state, and when the electrophoretic liquid is converted into the non-Newtonian fluid, the electrophoretic particles are static or move very slowly in the electrophoretic liquid, so that the electrophoretic particles can realize the stable state in the non-Newtonian fluid state.

Specifically, the conversion between the newtonian fluid and the non-newtonian fluid of the electrophoretic fluid is generated by controlling an alternating electric field, the long skeleton polymer chain or the mixed particles are the non-newtonian fluid when the physical or chemical adsorption crosslinking is performed, the crosslinking structure of the electrorheological material is destroyed when the alternating electric field controls the vibration of the electrophoretic particles, and the electrophoretic fluid is represented as the newtonian fluid.

Specifically, the material with electrorheological effect has not only oleophilic organic segment, but also one or more of the following functional segments of functional groups: -COO-, -NHCO-, -SO2Cl, -CH2CH 2-.

Specifically, the material with the electrorheological effect comprises inorganic nanoparticles or high polymer oligomers such as hydrogenated castor oil, glycerol, polyamide wax powder, superfine kaolin, superfine silicon dioxide, polyisobutylene and the like, and the material with the electrorheological effect is a positive electrorheological material or a reverse electrorheological material.

Specifically, the solvent is one of pure water, ethanol, butanol, benzene, toluene, xylene, trimethylbenzene, carbon tetrachloride, dichloromethane, tetrachloroethylene, an alkane solvent or an isoparaffin solvent, silicone oil, vegetable oil and castor oil.

Specifically, the charge control agent is a cationic surfactant, an anionic surfactant, a nonionic surfactant or a zwitterionic surfactant; the charge control agent is one or more of the following combinations, wherein:

the cationic surfactant is: octadecyl trimethyl ammonium chloride or N, N dimethyl dodecyl amine;

the anionic surface activity is as follows: sodium dodecylbenzene sulfonate or sodium ethoxyethyl sulfate;

the nonionic surfactant is: alkyl alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether;

the zwitterionic surfactant is as follows: ethoxylated nonylphenol sulfosuccinic acid half ester disodium salt or dodecyl dimethyl betaine.

Specifically, the stabilizer is polyvinylpyrrolidone.

Specifically, the electrophoretic particles in the electrophoretic fluid may be at least one. The electrophoretic liquid selects two electrophoretic particles with different colors to combine better. Examples may include Al₂O₃Electrophoretic fluid of white electrophoretic particles, and electrophoretic fluid containing Al₂O₃White electrophoretic particles and Fe₂O₃Electrophoretic fluid of red electrophoretic particles, and BaSO-containing electrophoretic fluid₄White electrophoretic particles, carbon black electrophoretic particles and organic red electrophoretic particles.

From the above description, the beneficial effects of the present invention are: the electrorheological effect of the electrophoretic particles is an inverse electrorheological fluid principle, the inverse electrorheological fluid is a non-Newtonian fluid formed by the ability that materials with electrorheological effect added into an electrophoretic fluid system have a network structure formed by mutual physical crosslinking when in a non-conductive state, and the electrophoretic particles are broken to form the Newtonian fluid when impacting the crosslinked network structure under the action of field intensity when in a conductive state, and the motion speed of the particles is increased at a speed which is multiplied by the reduction of the viscosity of the electrophoretic fluid system. The electrophoretic particles have high shearing strength, the cost of various raw materials is saved by the method, and the bistable effect can be ensured under the condition of ensuring the response time of the electronic paper.