SWELLING DYNAMICS OF A GEL UNDERGOING VOLUME TRANSITION

The swelling dynamics of a gel undergoing the volume transition is stu died theoretically for one dimensional case. It is assumed that there is a sharp interface between the swollen region and the unswollen regi on. The position of the interface and the volume change of the gel is calculated as a function of time by numerical simulation and analytica l calculation. It is shown that (i) the characteristic time of the swe lling is proportional to L0(2)zeta/\sigma(c)\(L0, zeta and sigma(c) be ing the gel size, the friction constant and the transition stress resp ectively), which diverges at the equilibrium transition temperature an d that (ii) the volume of the gel increases in proportion to square-ro ot t until it reaches the final volume.