Traditional ceramic-based electronics are based on rigid and planar wafer-based 2D technologies. Polymer substrates for electronic devices are of intense interest to offer opportunities to replace these conventional electronic substrates and to yield compliant, stretchable, and 3D electronics. Liquid crystal elastomers (LCEs) have attracted considerable attention as stimuli-responsive materials because they undergo large, reversible strain on heating and because this stimulus-response can be controlled through directed self-assembly. We hypothesized that these materials could serve as substrates for responsive electronics. Here, we discuss using programmable shape-morphing LCEs as substrates for electronic devices that are flat during processing but then morph to 3D shapes for use (<b>Figure 1</b>). We design processes to fabricate a variety of electronic devices on LCEs including conductors, capacitors, antennas, and biomedical microelectrode arrays (MEAs). For example, patterning twisted nematic orientation within the substrate can be used to create a bio-inspired helical 3D geometry in electronic devices that stretch up to 100% with less than a 5% change in electrical performances. Moreover, we discuss self-morphing LCE antennas which can dynamically change the operating frequency from 2.7 GHz (room temperature) to 3.3 GHz (-65 °C). Finally, we describe LCE-based MEAs for <i>in vitro</i> neuronal recordings that demonstrate that LCEs are non-cytotoxic and act as a stable encapsulation over 30 days in physiological conditions.

Designing liquid crystal elastomers as substrates for 3D electronics

2019 Spring National Meeting

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