Abstract

Synthesis of Temperature-Responsive Soft Microgels of Any Shape Using Stop-Flow Lithography

Hanna Wolff, Research Assistant, Chemical Process Engineering, RWTH Aachen University

Stop-flow lithography is a microfluidic method for the fabrication of µm-sized particles with complex shapes. Such particles can be used as building blocks for tissue engineering or soft micro-robotics. Especially, soft and responsive materials are beneficial for these applications; yet, the fabrication of soft responsive particles with complex shape has been rarely reported. In the present work, the technique of stop-flow lithography is used to fabricate soft temperature-responsive microgels with a complex shape. This combination of microgel properties is achieved by using N isopropyl acrylamide (NIPAm) monomer along with crosslinker in the reaction solution. Within the investigations, the polymerization parameters and influences on crosslinking the NIPAm monomer are determined and show the necessity of a threshold amount of crosslinker to form stable microgels. Furthermore, by varying the crosslinker concentration, the stiffness of the microgels can be tailored from very soft to comparably stiff. Moreover, these soft microgels of complex shape show a responsive behavior to temperature making them an excellent building block for life-like responsive tissue engineering.