Fabrication of Thermoresponsive and Multimaterial Hydrogel Sheets by Spatially Controlled Aspiration and Interconnection of Microgel Building Blocks

Polymer materials made from hierarchically assembled building blocks form a promising material class for engineering complex systems with integrated functionality for biological or electronic applications. Herein, this work utilizes an aspiration-based process involving a hole-bearing glass plate to align and interconnect acrylamide- and N-isopropylacrylamide-based microgels fabricated via emulsion formation in 3D-printed microfluidics. By tuning hole diameter and inter-hole distance as well as microgel deformability, mechanically stable, freestanding microgel constructs are obtained, which withstand shaking, ultrasonication, and swelling-shrinking cycles. By segmentally controlling aspiration at the hole-bearing glass plate, freestanding multimaterial sheets consisting of two different microgel species are obtained. The microgel assembly process is the first step toward fabricating hydrogel-based materials with spatially controlled functionality, which is an essential step toward system integration in polymer materials.

Automated summary

This work utilizes an aspiration-based process involving a hole-bearing glass plate to align and interconnect microgels and creates mechanically stable, freestanding microgel constructs. Segmentation control of the aspiration process enables the formation of multimaterial sheets consisting of different microgel species. This research is a crucial step towards fabricating hydrogel-based materials with spatially controlled functionality.