3D Printed Liquid Crystal Elastomer Actuator with Innervated Core
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Solution Overview
Problem
Existing methods for programming director alignment in liquid crystal elastomers are limited to thin films and one-dimensional motifs, restricting their application in soft robotics and shape-shifting architectures.
Innovation Solution
Extrusion-based 3D printing is used to induce director alignment along the print path, enabling the fabrication of 3D liquid crystal elastomers with programmed shape-morphing behavior and actuation response through a core-shell structure, where the core material activates the nematic-to-isotropic transition of the liquid crystal elastomer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional methods are used to program director alignment in liquid crystal elastomers, then thin films and one-dimensional motifs can be achieved, but 3D shape-morphing behavior and complex actuation responses cannot be programmed
Solution Approach 1:
The patent transitions from traditional 1D director alignment in thin films to 3D director alignment throughout the bulk elastomer volume. This is achieved by incorporating liquid crystal aligning agents directly into the bulk polymer matrix during fabrication, enabling complex three-dimensional shape-morphing behaviors that were previously impossible with surface-only alignment methods.
Solution Approach 2:
The patent implements spatially varying director alignment throughout different regions of the bulk elastomer. By controlling the distribution and orientation of liquid crystal aligning agents within the polymer matrix, distinct local alignment patterns can be programmed in different zones, enabling complex global shape changes through coordinated local deformations.
2Manufacturing precision
If bulk liquid crystal elastomers with mechanically induced alignment are used, then three-dimensional structures can be achieved, but alignment precision and programmability are limited
Solution Approach 1:
The patent incorporates liquid crystal aligning agents into the bulk polymer matrix during the fabrication process itself, rather than attempting to induce alignment afterward through mechanical means. This preliminary incorporation of alignment-directing elements ensures precise and uniform director alignment is established during curing, eliminating the need for complex post-fabrication mechanical alignment procedures.
Solution Approach 2:
The patent replaces traditional mechanical induction methods (such as stretching or rubbing during curing) with a chemical approach using liquid crystal aligning agents embedded in the polymer matrix. These agents provide molecular-level alignment templates that guide polymer chain orientation during curing, achieving superior alignment precision without complex mechanical operations.
3Use of energy by moving object
If liquid crystal elastomers are designed for large contraction, then high energy density actuation is achieved, but control precision and reversibility become challenging
Solution Approach 1:
The patent utilizes the nematic-to-isotropic phase transition of liquid crystals to achieve reversible actuation. By programming the director alignment in the nematic phase and then heating above the transition temperature to the isotropic phase, large contractions are achieved. Upon cooling, the system reversibly returns to the nematic phase with restored director alignment, enabling repeatable actuation cycles with high energy density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for high-energy, reversible actuation with self-sensing capabilities and closed-loop control, enabling the production of innervated liquid crystal elastomer actuators that can contract by over 50% and lift weights exceeding their own mass, with programmable and repeatable strain and resistance changes.
Implementation Method 1
These elastomers include a crosslinked polymer network that contains rigid mesogens, which may actuate when heated above their nematic-to-isotropic transition temperature (TNI) or exposed to another stimulus
Implementation Method 2
The core material may comprise an electrically conductive material... the core material comprises a liquid metal or a polymer
Data Source
AI summary
A method of forming an innervated liquid crystal elastomer (iLCE) actuator comprises extruding a filament through a nozzle moving relative to a substrate, where the filament has a core-shell structure including a shell comprising a liquid crystal elastomer surrounding a core configured to induce a nematic-to-isotropic transition of the liquid crystal elastomer. The filament is subjected to UV curing as the filament is extruded, and the filament is deposited on the substrate as the nozzle moves. A director of the liquid crystal elastomer is aligned with a print path of the nozzle, and a 3D printed architecture configured for actuation is formed.