Dynamic Light Scattering Investigation of Pnipam-Co-Maa Microgel Solution

The paper presents results of a study of the effect of the environment temperature and pH on the size of particles based on poly N (isopropylacrylamide) chain. The tested substance was the copolymer PNIPAM-co-MAA. The particle size measurements were performed by dynamic light scattering. It was found that the copolymer tested reacts specifically to temperature increase by shrinking more than two times. Important for stabilization of the structure are the chemical groups -COOH present in methacrylic acid that undergoes dissociation. Gradual increase in temperature results in a decrease in the dissociation constant, in binding of protons and thus causes shrinkage of the entire particle. It was also shown that PNIPAM-co-MAA in high concentrations undergoes crystallization.

The Effect of Temperature on the Dispersion of a-Mangostin in PNIPAM Microgel System

a-Mangostin was extracted from the pericarp of the Malaysian local Garcinia mangostana linn., The structure was characterised by Infrared red, UV-Visible and Nuclear Magnetic Resonance spectroscopic data. The fluorescence peak at 500nm in ethanol was not observed in PNIPAM microgel solution. The increase of colloidal size of the gel in the presence of a-mangostin was studied by Dynamic Light Scattering and Transmission Electron Microscope. The size of the particle also increases with increasing temperature up to 45°C after which it began to shrink. The TEM micrograph at 45°C showed a uniformly structured pattern of the gel occurs in the range of the lowest solution critical temperature.

The Effect of Temperature on the Dispersion of a-Mangostin in PNIPAM Microgel System

u-Mangostin was extracted from the pericarp of the Malaysian local Garcinia mangostana linn., The structure was characterised by Infrared red, UV-Visible and Nuclear Magnetic Resonance spectroscopic data. The fluorescence peak at 500nm in ethanol was not observed in PNIPAM microgel solution. The increase of colloidal size of the gel in the presence of u-mangostin was studied by Dynamic Light Scattering and Transmission Electron Microscope. The size of the particle also increases with increasing temperature up to 45°C after which it began to shrink. The TEM micrograph at 45°C showed a uniformly structured pattern of the gel occurs in the range of the lowest solution critical temperature.