| 초록 |
The molecular weight effects on the colloidal particle sizes of poly(styrene-co-styrenesulfonate) ionomers in THF/water (1/99) mixture were investigated. For the acidic copolymers, the size of colloidal particle of relatively low MW sample was found to decrease strongly and then remain more or less constant at ca. 11 nm with upon dilution. This suggested that the acid polymer chains in a relatively high concentration formed colloidal particles that aggregated together due to the interactions between the particles having relatively non-polar surface. For high MWs copolymers, the colloid sizes did not change much with upon dilution, with slightly larger sizes for the higher MW samples at comparable solution concentrations. This result could be understood; the higher MW copolymer had the longer polymer chain, leading to the larger colloid. The size of colloids was found to increase slightly upon dilution due to the repulsion of ionic groups on the surface. |
