Method and apparatus for preparing monodomain liquid crystal elastomer smart fiber

Patent metadata

Field	Value
Publication number	US-12227879-B2
Application number	US-202318220471-A
Country	US
Kind code	B2
Filing date	Jul 11, 2023
Priority date	Jan 17, 2022
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

A method for preparing a monodomain liquid crystal elastomer smart fiber incudes: during cross-linking process of the liquid crystal elastomer, drawing of liquid crystal elastomer fibers with uniform diameter from a polymer solution when the viscosity of the cross-linked polymer solution increases to a point where filaments can be drawn; heating by an infrared lamp to form filamentous liquid crystal elastomer fiber; natural air drying to remove excess solvent in the fiber; and stretching and collection of the fiber, followed by placement of the fiber, whereby the monodomain liquid crystal elastomer smart fiber is obtained. The method uses a one-step liquid phase drawing method, which is simple and suitable for large-scale industrial production and enables continuous preparation of high-strength, large-deformation reversible shape memory liquid crystal elastomer fiber with uniform and controllable diameter, breaking through the limitations of the size, strength and driving performance of existing liquid crystal elastomers.

First claim

The invention claimed is:

1. A method for preparing a monodomain liquid crystal elastomer smart fiber, comprising: during crosslinking process of the liquid crystal elastomer, drawing of liquid crystal elastomer fibers with uniform diameter from a polymer solution when a viscosity of the cross-linked polymer solution increases to a point where filaments are drawn; heating by an infrared lamp to form filamentous liquid crystal elastomer fiber; natural air drying to remove excess solvent in the fiber; and stretching and collection of the fiber; followed by placement of the fiber, whereby the monodomain liquid crystal elastomer smart fiber is obtained,
wherein the method comprises the following operation steps:
S1: adding a liquid crystal monomer and a chain extender to a solvent, stirring and mixing the same evenly, adding a catalyst and stirring airtightly until a reaction ends, whereby a prepolymer is obtained;
S2: adding a crosslinking agent to the prepolymer obtained in step S1, mixing and stirring the same evenly, adding the catalyst again, and continuing airtight stirring to obtain a polymer solution;
S3: when the viscosity of the polymer solution obtained in step S2 increases to the point where filaments are drawn, drawing liquid crystal elastomer fibers with uniform diameter from the polymer solution, heating the fibers by irradiation with an infrared lamp, followed by continuous rotation, whereby filamentary liquid crystal elastomer fibers are continuously prepared;
S4: drying the prepared liquid crystal elastomer fibers by natural air to remove the excess solvent in the fibers, and then stretching and collecting the fibers, wherein the stretching rate is 50-90%, followed by a placement after which the monodomain liquid crystal elastomer smart fiber is obtained,
wherein the chain extender is one or more of ethylene glycol bis(3-mercaptopropionate) (GDMP), 1,4 butanediol bis(mercaptopropionate) (BDBT), ethylene glycol dimercaptoacetate (EGBMA), 3,6-dioxa-1,8-octanedithiol (EDDET), bis(2-mercaptoethyl)ether (DSH), 1,3-propanedithiol (PDT), 1,6-Hexanedithiol (HDT) and 1,10-decanedithiol (DDT), and
wherein the crosslinker is pentaerythritol tetrakis (3-mercaptopropionate) (PETMP).

2. The method for preparing a monodomain liquid crystal elastomer smart fiber according to claim 1 , further comprising the following steps:
S1.1: prior to S2, adding a conductive filler to the prepolymer obtained in step S1, stirring the same airtightly until even mixing is achieved, followed by ultrasonic dispersion.

3. The method for preparing a monodomain liquid crystal elastomer smart fiber according to claim 1 , wherein the molar ratio of the liquid crystal monomer to the chain extender is 1:0.8-0.95.

4. The method for preparing a monodomain liquid crystal elastomer smart fiber according to claim 1 , wherein the catalyst is one of di-n-propylamine (DPA) and triethylamine (TEA).

5. The method for preparing a monodomain liquid crystal elastomer smart fiber according to claim 1 , wherein a molar ratio of the liquid crystal monomer to the crosslinker is 1:0.025-0.1.

6. The method for preparing a monodomain liquid crystal elastomer smart fiber according to claim 2 , wherein the conductive filler is one or more of carbon nanotubes, carbon black, and graphene.

7. An apparatus for preparing a monodomain liquid crystal elastomer smart fiber, comprising:
a main frame;
a translation mechanism including a screw drive assembly, the screw drive assembly being installed on the main frame for driving a sample tank to translate in a horizontal direction;
a drawing mechanism including a drawing drum fixed on the main frame through mounting seats on both sides and arranged above a translation path of the sample tank, and a second motor to drive the drawing drum to rotate, wherein nascent fibers drawn by a drawing head are fixed on the drawing drum which rotates to wind the drawn fibers on a surface thereof;
a collection mechanism including a collection drum also fixed on the main frame through mounting seats on both sides and arranged immediately above the drawing drum, and a third motor to drive the collection drum to rotate, wherein the collection drum rotates to wind the fibers unwound from the drawing drum with tension; and
an infrared heating mechanism including a plurality of infrared lamps installed in parallel on the main frame and located on the side of the main frame away from the drawing drum, wherein the infrared lamps are arranged to irradiate and heat the fiber to volatilize a solvent in the fiber for solidification.

8. The apparatus for preparing a monodomain liquid crystal elastomer smart fiber according to claim 7 , wherein the plurality of said infrared lamps is divided into three groups that are arranged in order from top to bottom, wherein the bottom group of infrared lamps is parallel to the drawing drum, the remaining two groups of infrared lamps are respectively installed at a height between the drawing drum and the collection drum, and wherein a set power of each group of the infrared lamps increases as the height increases.

Assignees

• Univ Changzhou
• Univ Yangzhou
• Yangzhou Technology Innovation Research Center For Carbon Neutrality Of Yangzhou Univ

Inventors

• Yuan Ningyi
• Dong Xu
• Li Lvzhou
• Ding Jianning
• Zhou Xiaoshuang
• Jiang Yaoyao

Classifications

• C09K2019/2078

  Ph-COO-Ph-COO-Ph · CPC title

• B29D99/0078

  Producing filamentary materials · CPC title

• D10B2401/04

  Heat-responsive characteristics · CPC title

• D10B2401/046

  Shape recovering or form memory · CPC title

• D10B2401/041

  thermoplastic; thermosetting · CPC title