Shape-Programmable Liquid Crystal Elastomers for High Work Capacity
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Solution Overview
Problem
Existing liquid crystal elastomers (LCEs) face limitations in maintaining complex director orientations and achieving high thickness without losing alignment, which restricts their ability to exert muscle-like contractile forces and generate significant work due to finite anchoring energies of surface interactions.
Innovation Solution
The synthesis of shape-programmable liquid crystal elastomers involves filling an alignment cell with liquid crystal monomers that align and polymerize with a dithiol chain transfer agent, allowing for registered alignment of multiple LCE layers to enhance director orientation and thickness, thereby increasing work capacity and force output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If LCE thickness is increased to enhance work capacity, then work capacity and force output improve, but director orientation alignment is lost due to finite anchoring energies
Solution Approach 1:
The LCE is divided into multiple discrete layers, each independently aligned and maintained with proper director orientation through surface anchoring. By segmenting the thick LCE into thinner layers, each layer can maintain alignment stability while collectively achieving high thickness and enhanced work capacity.
Solution Approach 2:
Multiple LCE layers are nested or stacked together to form a thicker composite structure. Each layer retains its director orientation alignment, and the cumulative effect of multiple aligned layers achieves the desired high thickness while preserving overall alignment stability.
2Adaptability or versatility
If surface alignment is used to program complex director orientations, then shape programmability improves, but alignment is lost in thick samples due to finite anchoring energies
Solution Approach 1:
The thick sample is segmented into multiple thinner layers, each capable of maintaining surface-induced alignment. This segmentation allows complex director orientations to be programmed in each layer while preserving alignment throughout the entire thick sample structure.
Solution Approach 2:
The solution transitions from a single-dimensional thick sample to a multi-layered structure, adding the dimension of layering. This allows surface alignment to effectively program director orientations in each layer while the stacked configuration maintains overall alignment in the thick composite sample.
3Stability of the object's composition
If polysiloxane LCEs are mechanically loaded to align mesogens, then alignment is achieved, but the process is limited and complex
Solution Approach 1:
The mechanical loading alignment process is replaced with surface alignment techniques. Instead of applying mechanical stress to align mesogens, surface alignment layers are used to induce and maintain proper mesogen orientation through surface interactions, simplifying the alignment process.
Solution Approach 2:
Surface alignment layers are applied in advance to establish the desired mesogen orientation before the LCE is fully formed or used. This preliminary action of aligning mesogens through surface interactions eliminates the need for subsequent complex mechanical loading processes.
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 enables LCEs to exhibit large, reversible shape changes with strains greater than 475%, increasing the out-of-plane work capacity by an order of magnitude to nearly 20 J/kg and allowing the material to displace loads over 2500 times its own weight, while maintaining surface-induced alignment and optical clarity.
Implementation Method 1
The liquid crystal monomers align to a surface of the alignment cell
Implementation Method 2
liquid crystal monomers that align and polymerize with a dithiol chain transfer agent
Implementation Method 3
exhibit large, reversible shape changes with strains greater than 475%
Implementation Method 4
The molecular orientation governs the anisotropy of macroscopic mechanical response
Implementation Method 5
arranging a plurality of liquid crystal elastomers such that a director orientation of each liquid crystal elastomer of the plurality is in registered alignment with an adjacent liquid crystal elastomer of the plurality
Data Source
AI summary
Shape-programmable liquid crystal elastomers. The shape-programmable liquid crystal elastomers being synthesized by filling an alignment cell with liquid crystal monomers. The liquid crystal monomers align to a surface of the alignment cell and then are polymerized with a dithiol chain transfer agent. The alignment cell is configured to impose a director orientation on a portion of the shape-programmable liquid crystal elastomer. For some embodiments, liquid crystal elastomer laminates are prepared by arranging a plurality of liquid crystal elastomers such that a director orientation of each liquid crystal elastomer of the plurality is in registered alignment with an adjacent liquid crystal elastomer of the plurality. The arrangement is secured and the plurality of liquid crystal elastomers cured.