Simultaneous crosslinking induces macroscopically phase-separated microgel from a homogeneous mixture of multiple polymers

Title: Simultaneous crosslinking induces macroscopically phase-separated microgel from a homogeneous mixture of multiple polymers
Authors: Yuta Kurashina, Mio Tsuchiya, Atsushi Sakai, Tomoki Maeda, Yun Jung J. Heo, Filippo Rossi, Nakwon Choi, Miho Yanagisawa, Hiroaki Onoe
Journal: Applied Materials Today, Vol 22, Number 100937 (2021)
DOI: 10.1016/j.apmt.2021.100937

Abstract:
This paper reports a unique phase separation behavior, a simultaneous-crosslinking-driven phase separation in co-gelation (SPSiC) core-shell microgel that spontaneously forms from a homogeneous pre-gel solution of multiple polymers. The SPSiC microgel, composed of an alginate shell and an N-isopropylacrylamide (NIPAM) core, were synthesized by a single fabrication step wherein a mixed pre-gel solution of sodium alginate and NIPAM monomer was ejected by centrifugation with photo-polymerization and ion crosslinking instantaneously. Phase separation was modeled by varying the degree of polymerization and the size of the polymer chain. Moreover, an implantable, multi-functional drug delivery system combined with a transdermal glucose sensor was demonstrated with core-shell Janus SPSiC microgels. This work shows a macroscopic phase separation behavior, which occurs during the gelation process, and also provides a simple and unique methodology to create multifunctional bio-microprobes.

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