Structural changes in hydrogels immersed in a linear polymer solution, studied by SANS

The structural changes in polyelectrolyte gels immersed in a linear polymer solution were studied by the small-angle neutron scattering technique. Two cases were considered: (i) when the gel absorbed mainly water and did not interact with the linear polymer; and (ii) when a linear polymer formed an interpolymer complex with the gel and thus penetrated the network. It was s hown that in the first case the gel contracted almost as a unit due to the osmotic pressure difference. In the second case the gel contracted through microphase separation. (C) 2000 Elsevier Science Ltd. All rights reserved.