The shrinking mechanism of comb-type poly(N-isopropylacrylamide) (NIPA) gel was investigated by small-angle neutron scattering (SANS). The SANS reveals that the microdomain structure with characteristic spacing of 460 A is developed in the comb-type NIPA gel during the shrinking process. This suggests that the freely mobiles grafted chains show the rapid dehydration to make tightly packed globules with temperature, followed by the subsequent hydrophobic intermolecular aggregation of the dehydrated graft chains. These aggregations of the NIPA chains contribute to an increase in void volume, which allows the gel having a pathway of water.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering