4D printing method for controlling deformation of liquid crystal elastomer material

A liquid crystal elastomer and material deformation technology, applied in the direction of additive manufacturing, manufacturing tools, additive processing, etc., can solve the problems of limiting the deformation flexibility of intelligent drives, and achieve the effect of multi-stage reversible shape change

Pending Publication Date: 2022-01-28
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, 4D printing liquid crystal elastomers are mostly homogeneous, which greatly limits their deformation flexibility as an intelligent driver, and the material properties of 3D printing parts are given during the printing process, which can be used in the printing process. Parameter Variation Programs Deformation Behavior of Materials

Method used

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  • 4D printing method for controlling deformation of liquid crystal elastomer material
  • 4D printing method for controlling deformation of liquid crystal elastomer material
  • 4D printing method for controlling deformation of liquid crystal elastomer material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The experimental materials were prepared by the addition method, and the liquid crystal monomer C6m (RM82), n-butylamine and photoinitiator were mixed with a mass ratio of 1:1:0.01. Seal the reaction flask with a bottle stopper with a stirring hole, put the flask into an oil bath at a temperature of 100° C., and then use a stirring device to stir the mixture at a speed of 80 / min for 18 hours. After the reaction, the liquid crystal ink was placed in a refrigerator at -5°C for ice bath quenching for 2 hours, and then the material was placed into an extrusion printing syringe for direct-write photocuring printing.

Embodiment 2

[0035] Use customized direct-write extrusion head printers for material build-up molding printing, printing devices such as figure 1 As shown, 1 is the direct writing extrusion head, and the material is placed in the extrusion head and extruded by air pressure. 2 is the material forming substrate, which can be driven by the sliding table below to move along the XYZ axis. 3 is the liquid crystal elastomer precursor material extruded on the molding substrate. 4 is the ultraviolet light curing head, which can emit 365nm ultraviolet light head to cure the printed sample. Since the photoinitiator IRGACURE 369 is added to the precursor material, it can cause further curing of the liquid crystal elastomer material under the irradiation of ultraviolet light. Polymerization fixes the orientation of the liquid crystal.

[0036] The distance between the UV curing head and the direct writing printing extrusion head is 50mm, and the super-condensing lens is selected as the lens of the UV...

Embodiment 3

[0043] Such as figure 2 A difference in crosslink density is introduced on both sides of a rectangular spline as shown, the left side is a region of high crosslink density fully cured using a high UV light meter with a total irradiance meter of 200mw / cm 2 , on the right is a lightly cross-linked area cured with low UV light metering, with a total irradiance metering of 50mw / cm 2 . At a low stimulation temperature of 120 °C, the low crosslink density region first undergoes phase transition shrinkage, causing length differences along the long sides, and the component bends in-plane toward the low crosslink density region, transforming from a rectangle to a semicircle. When the temperature continues to rise to the high stimulation temperature of 155°C, the fully cured high-crosslinking density region also undergoes phase transition shrinkage, and the semicircular sample continues to deform into a rectangular spline. Further, when the temperature continues to decrease, the recta...

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Abstract

The invention discloses a 4D printing method for controlling deformation of a liquid crystal elastomer material, the method comprises the following steps: after the material is extruded and deposited on a substrate, selectively curing the formed material by adopting an ultraviolet light sweeping mode, and adjusting the energy intensity of ultraviolet light emitted by an ultraviolet light controller, or adjusting the relative movement speed between the ultraviolet light controller and the forming material or adjusting the distance between the ultraviolet light controller and the forming material to control the total irradiation dose of the ultraviolet light received by different areas so that the crosslinking density of the different areas of the material is controlled. According to the method, different areas of a liquid crystal elastomer precursor sample piece printed in a direct-writing mode are irradiated with ultraviolet light of different doses, so that different parts of the liquid crystal elastomer precursor sample piece generate different cross-linking densities, and the temperature of isotropic-non-isotropic conversion of the different parts is different. According to the invention, the multi-stage reversible shape change of the liquid crystal elastomer sample piece can be realized by utilizing the differential design of the printing structure and the crosslinking density in space.

Description

technical field [0001] The invention relates to the technical fields of additive manufacturing and intelligent polymer materials, in particular to a 4D printing method for controlling deformation of liquid crystal elastomer materials. Background technique [0002] Liquid crystal elastomers are smart materials that combine the properties of liquid crystals with those of polymers. It can complete its transformation from nematic state to isotropic state under the stimulation of external field, such as heat, light, magnetic field, etc., and its internal mesogen changes from orderly arrangement to disorder, which is manifested macroscopically The shape changes and the color changes, and this change is reversible. Due to its excellent excitation-response characteristics and good cycle characteristics, it can be used as a material for the manufacture of drivers and sensors. [0003] 3D printing, as a rapid prototyping additive manufacturing technology, can quickly manufacture pre...

Claims

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Application Information

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IPC IPC(8): B29C64/264B29C64/393B33Y30/00B33Y50/02
CPCB29C64/264B29C64/393B33Y30/00B33Y50/02
Inventor 何禹霖任露泉王振国吴千韩志武刘庆萍
Owner JILIN UNIV
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