Behavior of heterogeneous macromolecular structures Part I: Microgels and coated microgels

Abstract

Homopolymeric microgels composed of PMMA were prepared by emulsion polymerization in the presence of 0.5 % 1,4-butanediol divinylether (BVE) in an aqueous medium followed by careful removal of the soap. The microgels were coated with polystyrene (PS) by anionic grafting of living PS chains onto the surface. Both types of microgels were characterized by GPC and by static and dynamic light scattering in several solvents. A special model consisting of a hard core and a seam of dangling chains has been developed and applied to interpreting the light scattering data from the various solvents. The model gives consistent results, e.g. the core radius agrees well with the radius of gyration. In the coated microgels a strong expansion of the core as a result of the PS/ PMMA incompatibility is observed.

Polymer Networks in Research and Application

“…The inset Figure 12b gives the overstretching factors as a function of crosslinking density. Similar synergistic swelling was observed earlier [24] with star-microgels, i.e. a poly(methylmethacrylate) (PMMA) core covered by short poly(styrene) (PS) chains in 10 different organic solvents.…”

Swelling behavior of PMMA-g-PEO microgel particles by organic solvents

“…For true "hardsphere" particles, which are impenetrable to any solvent, the value would be 0.775 [20]. For microgel particles, which are swollen with solvent, the value would be about 0.5 [21][22][23]. Clearly, for the samples studied here, intermediate values were obtained.…”

Rheology of concentrated microgel solutions

“…Unfortunately, the exact crosslinked molecular structure of Carbopol 941 is unknown. Although preparing and characterizing model microgel systems is a formidable task [4,18], these results suggest that future work on wellcharacterized microgel solutions should be useful.…”