Thermal and osmotic deswelling of poly(NIPAM) microgel particles

• DOI: 10.1039/ft9969203385
• Publication Date: 2004-04-15T14:27:53Z
• Authors: Brian R. Saunders; Brian Vincent
• Keywords: Dispersity; Osmotic pressure; Particle (ecology)

The effects of temperature and added free polymer on the swelling poly(NIPAM)(NIPAM =N-isopropylacrylamide) microgel particles cross-linked with N,N′-methylene bisacrylamide have been investigated. were characterized by photocorrelation spectroscopy (PCS), TEM SEM measurements. Particle sizes determined invariably larger than those measured at 50 °C PCS. data suggest that dried an oblate spheroid shape. rate which poly(NIPAM) collapse swell in response to cycling between 28 60 was examined some hysteresis observed. Excluded [PEG, where PEG = poly(ethyleneglycol)] also caused deswelling 25 due osmotic pressure effects. Osmotic occurred presence monodisperse when molecular weight latter 1470 g mol–1. Higher polymers a general decrease extent (at fixed concentration PEG).