A temperature‐responsive polyurethane and its biocompatible and biodegradable nanohydrogels with uniform cross‐linking networks

We prepared a temperature-responsive polyurethane (PU) with a coil-to-globule transition temperature of 36 degrees C in aqueous media, by using polyethylene glycol-4,000 (PEG-4000), polycaprolactone diol-1,000 (PCL-1000), diphenylmethane diisocyanate-50, and hydroxyethyl acrylate. Nanohydrogels were synthesized from temperature-responsive PU through precipitation polymerization without employing a crosslinker. Due to the unique molecular structure of temperature-responsive PU, PU nanohydrogels have uniform cross-linking networks resulting in narrow volume phase transition temperature range, showing sensitive temperature responsiveness. Additionally, PEG and PCL segments provide PU nanohydrogels excellent biocompatibility and biodegradability, respectively. POLYM. ENG. SCI., 59:1517-1523 2019. (c) 2019 Society of Plastics Engineers