Additive-Manufactured Stochastic Polyimide Foams for Low Relative Permittivity, Lightweight Electronic Architectures.

Polyimides are widely utilized engineering polymers due to their excellent balance of mechanical, dielectric, and thermal properties. However, the manufacturing of polyimides into complex multifunctional designs can be hindered by dimensional shrinkage of the polymer upon imidization and post processing methods and inability to tailor electronic or mechanical properties. In this work, we developed methods to three-dimensional (3D) direct ink write polyimide closed-cell stochastic foams with tunable densities.

Enabling and Localizing Omnidirectional Nonlinear Deformation in Liquid Crystalline Elastomers.

Liquid crystalline elastomers (LCEs) are widely recognized for their exceptional promise as actuating materials. Here, the comparatively less celebrated but also compelling nonlinear response of these materials to mechanical load is examined. Prior examinations of planarly aligned LCEs exhibit unidirectional nonlinear deformation to mechanical loads.

Layered liquid crystal elastomer actuators.

Liquid crystalline elastomers (LCEs) are soft, anisotropic materials that exhibit large shape transformations when subjected to various stimuli. Here we demonstrate a facile approach to enhance the out-of-plane work capacity of these materials by an order of magnitude, to nearly 20 J/kg. The enhancement in force output is enabled by the development of a room temperature polymerizable composition used both to prepare individual films, organized via directed self-assembly to retain arrays of topological defect profiles, as well as act as an adhesive to combine the LCE layers.

Electrical Control of Shape in Voxelated Liquid Crystalline Polymer Nanocomposites.

Liquid crystal elastomers (LCEs) exhibit anisotropic mechanical, thermal, and optical properties. The director orientation within an LCE can be spatially localized into voxels [three-dimensional (3-D) volume elements] via photoalignment surfaces. Here, we prepare nanocomposites in which both the orientation of the LCE and single-walled carbon nanotube (SWNT) are locally and arbitrarily oriented in discrete voxels.

Synthesis of Elastomeric Liquid Crystalline Polymer Networks via Chain Transfer.

Materials capable of complex shape changes have broad reaching applications spanning biomimetic devices, componentless actuators, artificial muscles, and haptic displays. Liquid crystal elastomers (LCE) are a class of shape programmable materials which display anisotropic mechanical deformations in response external stimuli. This work details a synthetic strategy to quickly and efficiently prepare LCEs through the usage of chain transfer agents (CTA).

Pixelated Polymers: Directed Self Assembly of Liquid Crystalline Polymer Networks.

Polymeric materials are pervasive in modern society, in part attributable to the diverse range of properties that are accessible in these materials. Polymers can be stiff or soft, dissipative or elastic, adhesive or nonstick. Localizing the properties of polymeric materials can be achieved by a number of methods, including self-assembly, lithography, or 3-d printing.