Affiliation:
1. Department of Chemical Engineering 4306 Wegmans Hall University of Rochester Rochester NY 14627‐0166 USA
2. Laboratory for Laser Energetics University of Rochester 250 East River Road Rochester NY 14623‐1299 USA
3. Department of Electrical Engineering and Computer Engineering University of Nebraska‐Lincoln Lincoln NE 68588 USA
Abstract
AbstractTwo‐photon printing is accomplished using a photobase generator, 2‐(2‐nitrophenyl)‐propyloxycarbony tetramethyl guanidine, to locally catalyze thiol‐ene coupling between multifunctional monomers while mitigating chain‐growth polymerization with free radical scavengers. Microstructures printed from base‐catalyzed resins exhibit higher resolution (linewidths < 400 nm) and lower print error (<3%) than analogous microstructures printed using a photosensitive, free radical initiator. Further, Raman spectroscopy reveals that resins polymerized using the photobase generator in the presence of free radical scavengers exhibit higher selectivity of thiol‐ene coupling over radical polymerization, resulting in stiffer, more uniform polymer networks. The base‐catalyzed resins are capable of producing 3D microstructures printed with high accuracy and minimal post‐processing defects. A direct comparison between free radical and base‐initiated resins highlights the need for mindful consideration of how chemical reaction pathway influences printability and network end‐properties when designing resins.
Funder
National Nuclear Security Administration