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

Abstract

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.

Multi-Responsive Behaviors of Copolymers Bearing N-Isopropylacrylamide with or without Phenylboronic Acid in Aqueous Solution

“…Dynamic light scattering (DLS) is a technique in physics that can be applied to determine the size distribution profile of small particles in suspension or polymers in solution [ 10 ]. Because it is easy to change physical conditions of working solutions, DLS technique is often used to examine D H of PNIPAAm-mediated materials changed in response to the changes of environmental parameters, in order to illustrate the stimulus responses of intelligent composites [ 11 , 12 , 13 ]. Recently, scholars had also conducted prominent works in the synthesis of smart materials carrying NIPAAm and PBA, and further investigated their dual responses to temperature and glucose by means of the DLS technique [ 14 , 15 , 16 , 17 , 18 ].…”

Temperature Response of Rhodamine B-Doped Latex Particles. From Solution to Single Particles

“…Hydrophobic rhodamine dyes can be directly entrapped within nanoparticles synthesized in situ by emulsion or miniemulsion polymerization of a hydrophobic vinylic monomer in the presence of the dye. To ensure that the dye is incorporated randomly and uniformly along the latex polymer backbone, rhodamine-labeled monomers are often used. − Hydrophilic water-soluble dyes like RhB ,, or rhodamine 6G , can also be directly incorporated into latex particles by emulsion polymerization. The process relies on in situ interaction of the dye molecules with the monomer and/or the growing polymer through hydrophobic and electrostatic interactions resulting in the dye being physically entrapped within the forming NPs.…”

Temperature dependent volume expansion of microgel in nonequilibria

“…The modeling has been performed with the aim of revealing some basic trends of the hybrid microgel formation, uncovered in [1]. Nevertheless, we are aware that there exist reverse processes which are not captured by presented model [27,28].…”