Monodisperse microspheres exhibiting discontinuous response to temperature change

Abstract

Poly(N-isopropylacrylamide) (PNIPAM) microspheres prepared so far did not exhibit discontinuous change in their properties at the lower critical solution temperature of PNIPAM. In order to create novel microspheres which have sharp temperature-responsiveness, we prepared several kinds of microspheres which had different structures of the thermosensitive shell. Among them, the microspheres whose shell was composed of acrylic acid (AAc)-containing hairy PNIPAM met our requirement, that is, incorporation of only 0.02% AAc into hairy PNIPAM shell was found to enable the properties of microspheres such as hydrodynamic size and electrophoretic mobility to change discontinuously at the critical temperature.