Topic
Methacrylic acid
About: Methacrylic acid is a research topic. Over the lifetime, 13058 publications have been published within this topic receiving 173201 citations. The topic is also known as: α-Methacrylic acid & 2-Methylacrylic acid.
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140 citations
TL;DR: The results demonstrate that the pH during synthesis has a significant impact on the composition and thus the properties of the microgel and its ability to be utilized as a stimuli responsive stabilizer for emulsions.
Abstract: Responsive polymer microgels can be employed for the preparation of stimuli-sensitive emulsions. The microgels used in this study are based on cross-linked copolymers including N-isopropylacrylamide and methacrylic acid. We conducted the synthesis under acidic and basic conditions to investigate the effect of changes of comonomer solubility on the microgel’s composition and ability to stabilize emulsions. The synthesis product was partially divided into two fractions by centrifugation. Raw product, collected supernatant, and purified microgel were characterized by means of light scattering, titration, as well as electrophoretic mobility. The ability of the three components to act as stabilizers was investigated by preparing the octanol/water emulsions and looking at their response to pH and temperature changes. The interfacial activity of the three components was characterized by means of the pendent drop technique. Furthermore, we investigated the response of the interface to dilatational stress using a ...
140 citations
TL;DR: In this article, the authors characterized the release kinetics in aqueous solution of two hydrophobic fluorescent probes (pyrene and phenanthrene) loaded into polymer micelles composed of the following diblock polymers.
Abstract: Micelles formed from amphiphilic block copolymers are known to effect aqueous solubilization of hydrophobic molecules. The kinetics of uptake or release can be monitored by fluorescence if the solubilizate is a fluorophore. The primary objective of this paper is the characterization of the release kinetics in aqueous solution of two hydrophobic fluorescent probes (pyrene and phenanthrene) loaded into polymer micelles composed of the following diblock polymers: polystyrene-block-poly(methacrylic acid), poly(tert-butyl acrylate)-block-poly(2-vinylpyridine), poly(2-vinylpyridine)-block-poly(ethylene oxide). Polystyrene latex particles were also studied for comparison. The release process was analyzed by a model of diffusion out of a sphere and the diffusion constants we measure are very small (10-18−10-16 cm2/s), depending on the core and probe. An exception is poly(2-vinylpyridine) for which the release was too fast for our measurement technique. Independent measurements of the partition coefficient of the...
139 citations
TL;DR: A novel approach to analyzing thin-film gradients with the reversed Wentzel-Kramers-Brillouin (WKB) approximation presents a powerful tool for the characterization of inhomogeneous hydrogels, which would otherwise be very difficult to capture experimentally.
Abstract: The structural features and swelling properties of responsive hydrogel films based on poly(N-isopropylacrylamide) copolymers with a photo-cross-linkable benzophenone unit were investigated by surface plasmon resonance, optical waveguide mode spectroscopy, and atomic force microscopy. The temperature-dependent swelling behavior was studied with respect to the chemical composition of the hydrogel polymers containing either sodium methacrylate or methacrylic acid moieties. In the sodium methacrylate system, a refractive index gradient was found that was not present in the free acid gel. This refractive index gradient, perpendicular to the swollen hydrogel film surface, could be analyzed in detail by application of the reversed Wentzel-Kramers-Brillouin (WKB) approximation to the optical data. This novel approach to analyzing thin-film gradients with the WKB method presents a powerful tool for the characterization of inhomogeneous hydrogels, which would otherwise be very difficult to capture experimentally. In AFM images of the hydrogel layers, a macroscopic pore structure was observed that depended on the polymer composition as well as on the swelling history. This pore structure apparently prevents the often-observed skin barrier effect and leads to a quickly responding hydrogel.
139 citations
TL;DR: Graft copolymer networks exhibiting pH-dependent swelling behavior due to the formation of interpolymer complexes were prepared by free radical solution polymerization of methacrylic acid and poly(ethylene glycol) monomethacrylate as mentioned in this paper.
Abstract: Graft copolymer networks of poly(methacrylic acid-g-ethylene glycol) exhibiting pH-dependent swelling behavior due to the formation of interpolymer complexes were prepared by free radical solution polymerization of methacrylic acid and poly(ethylene glycol) monomethacrylate. Dynamic swelling studies established the swelling/deswelling process due to hydrogen bonding. Additionally, the effects of copolymer composition, graft chain molecular weight, and environmental pH on network structure were studied. The average network correlation length changed significantly due to changes in environmental pH. The largest changes in network structure were observed in gels containing nearly equimolar amounts of methacrylic acid and ethylene glycol and the longest molecular weight poly(ethylene glycol) grafts. Water diffusion coefficients, determined through dynamic swelling analysis, varied by 2 orders of magnitude between the uncomplexed and complexed states.
138 citations