(56f) Glass-Forming Polymer Networks for Shape-Memory Contact Printing

Current methods for microscale pattern transfer fail to combine high feature resolution, ability to pattern large areas, high throughput and cost effectiveness. Over the past years, several researchers have demonstrated how films of shape-memory polymers can exhibit topographical memory, leading to switchable adhesion or optical properties. We are designing and developing new stimuli-responsive materials to ultimately enable high fidelity pattern transfer by thermal modulation of the elastomeric contact printing process.

Different glass forming polymers that can withstand high elongation and store large amounts of elastic strain energy in compression are under investigation. Two systems will be described: (i) small molecule thiol-ene networks that are softened by addition of dithiol reagents, and (ii) glass forming t-butyl acrylates that are lightly crosslinked. Their shape-memory behavior in tension and in compression will be reported. Furthermore, a custom-built materials testing / contact printing apparatus will be used to set compressive strain between two soft surfaces while measuring stress and contact area. Contact mechanics experiments are modeled and interpreted using finite element analysis to offer deeper insight to the nature of contact and detachment.