UC Santa Barbara

Recently, skin-interfacing sensors and electronics have become commonplace, gathering valuable medical data and information; however, these electronics necessitate the use of flexible materials and strong adhesives to conformally mount devices to the skin. To address this need, we aim to create a wrinkled system capable of relieving internal strain through self- expansion in response to stimuli, causing self-delamination from fragile skin and avoiding irritation or damage associated with adhesive removal. Firstly, I introduce my work towards the fabrication of pre-strained wrinkled morphologies. We rely on strategic layering of different commercially available polydimethylsiloxane (PDMS) elastomers, which possess variable mechanical properties such as stiffness and elasticity. By using a mechanical mismatch of “soft” and “stiff” elastomers, we are able to generate flexible and tunable wrinkled morphologies. Secondly, I discuss the initial efforts towards wrinkled substrate surface functionalization with stimuli-responsive small molecules and polymers. Specifically, I decorate our surfaces with polyethylene glycol tetrazole (PEG-Tet) star polymers, a biocompatible material that responds to light stimulation to generate fluorescent moieties and crosslinks. We highlight the utility of this optical reporter as a proof-of-concept chemistry for visualizing surface properties and “locking” our wrinkled morphologies in place. Future efforts will be expanded to the use of stimuli-responsive polymers capable of reversibly crosslinking to promote stimuli-responsive “unlocking” and subsequent device expansion.