Simultaneous Surface Color and Texture Changes Enabled by Liquid Crystal Elastomers
Abstract
Scientific Objectives: Materials and composites with multiple functional responsive properties are highly desirable in Army and DoD applications, such as smart cloths for soldier and equipment protection in different combat environments. However, existing stimuli-responsive materials can exhibit only one property or functional change. Recently, the PI has demonstrated the feasibility of achieving pixelized heating control in a polymer sheet where the pixels can be individually heated. Leveraging this new capability, the overarching goal of the proposed work is to gain fundamental understanding and develop a novel material system with simultaneous color and surface texture change enabled by liquid crystal elastomers (LCE) with embedded photonic crystals and heating elements. LCEs are widely used in active structures due to their attractive property of large reversible actuation upon environmental stimuli. But to date, they are only used for single function applications, such as shape morphing, artificial muscle, etc. To create pixelized deformation patterns for simultaneous reversible full-spectrum color and surface texture change by utilizing photonic crystals and heating elements, the proposed work will investigate fundamental questions, including 1) How to achieve tunable coloration during LCE fabrication and controllable color change during LCE actuation? 2) What are the governing factors in determining the temperature distribution in the pixelized LCE sheet? 3) How to integrate color change with surface texture creation and is it possible to achieve separate control? Methods to Be Employed: To answer these questions, the proposed work will conduct the following research tasks: 1) designing LCEs with embedded photonic crystals for tunable coloration by studying the dimension changes of LCEs during the fabrication process and actuation, 2) analyzing heat transfer to obtain three dimensional temperature distribution for actuation control, and 3) integrating color and surface texture change through non-uniform actuation of LCEs with pixelized heating control. These research tasks will be conducted through a combination of theoretical development, nonlinear finite element simulations, and experiments. Machine learning models will also be developed to accelerate the design. Significance: The proposed research will gain fundamental knowledge about how to imbue LCEs with structural color in its fabrication process and how to design surface texture using local hearting with integrated color change. The fundamental knowledge gained will enable an unprecedented novel material system that can possess simultaneous color and surface texture change. Such capability can be integrated with future critical applications, such as morphing UAVs or wearable electronics with adaptive color and texture capabilities. Also, since the fundamental studies on nanoscale pattern change can be applied to patterns of larger scales, the proposed work can inspire the design of multifunctional materials that couple shape morphing with the change of other properties, such as acoustic wave propagation and bandgaps. Therefore, the scientific understanding, the materials, and the methods gained in this proposed work will enable new strategies for next generation multifunctional programmable composite materials for Army and DoD applications. PI Career Relevance: The PI plans to develop her career with research focusing on the fundamental understanding and the development of innovative active materials and composites. This ECP project, along with her NSF Career Award on the investigation of magneto-thermo-viscoelastic behaviors of magnetic shape memory polymers, will serve as anchors for her career development. These two projects can also lead her to exciting new fields such as smart composites, wearable electronics, and advanced manufacturing for future Army and DoD applications.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 28, 2023
- Source ID
- W911NF2310176
Entities
People
- Renee Zhao
Organizations
- Army Contracting Command
- Stanford University
- United States Army