A Thermosensitive and Biodegradable Physical Gel with Chemically Crosslinked Nanogels as the Building Block

A triblock copolymer, poly(ethylene glycol)–poly(propylene glycol)–poly(ethylene glycol) was end‐capped by acryloyl groups using a biodegradable oligolactide as spacer, and such biodegradable amphiphilic macromers could form micelles in water. A nanogel was prepared via polymerizing macromers in a micelle, and a macroscopic physical gelation was found upon heating a concentrated aqueous nanogel suspension. Such a sol–gel transition with a chemically crosslinked nanogel as the building block was thermoreversible. While the hydrogel affords a promising injectable biomaterial; this research reveals new physics of the thermogelling mechanism of amphiphilic block copolymers. magnified image