Movement of thermo-sensitive gel in aqueous polymer solution

Abstract

In this study, we investigated the parameters concerning the moving of gel particles in the aqueous polymer solution in the upper heating system. thermo-sensitive gel particles containing N-isopropylacrylamide (NIPA) as a main component were used, which gel particles have the property of swelling at low temperature and shrunking at high temperature. For the aqueous polymer solution, 11 wt% of sodium polyacrylate (PAANa) solution was used. From experiments, density and temperature responsiveness of gel particles, density and viscosity of PAANa solution were measured. As a result, in the floating and sinking behavior, the gel particle density is larger than the solution density at 40°C, and the particles sinks because gravity acts stronger than buoyancy and resistance. At 10°C, the particle density becomes smaller than the solution density, so that the buoyant force acting on the particles exceeds the gravity and the resistance force, and it is considered that the particles float up.