Abstract:The swelling/deswelling behaviour of microgel particles in the bulk and at the surface was studied and correlated to their mechanical properties. We focused on two kinds of particles: pure PNIPAM and PNIPAM-co-AAc particles. It was shown that the two step volume phase transition found for PNIPAM-co-AAc particles in the bulk disappears after the adsorption at the surface and only a one step transition was identified. The transition temperature increased strongly with increasing the co-monomer content. The dependence of the Young's modulus of the adsorbed microgel particles on the temperature and the co-monomer content was discussed. The investigations were performed via DLS and SFM.

Poly(vinyllactams) form a class of non-ionic water-soluble polymers from which only poly-(1-vinyl-2-pyrrolidone) (PVP) is well known and has been investigated extensively. The homologues poly(1-vinyl-2-piperidone) (1, poly[l-(2-oxo-l -piperidyl)ethylene]) and poly(iV-vinylcaprolactam) (2, poly[l-(2-oxoperhydroazepin-l-yl)ethylene]) which are still soluble in water at room temperature have not yet been studied in aqueous solution. In this work the synthesis of these two polymers by radical polymerization in solution and the investigation of the dilute aqueous solution properties of these polymers by static and dynamic light scattering measurements are presented. Special attention is paid to the influence of the increasing hydrophobicity of these polymers on coil dimensions and structures in aqueous solution.

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Theseworkers claim that the complex of poly(acrylic acid) and polyethylene imine) can be transformed into a ladder-like structure of condensed nine-membered rings. See also: Ka-