Dependence of Temperature-Sensitivity of Poly(N-isopropylacrylamide-co-acrylic acid) Hydrogel Microspheres upon Their Sizes

Makino, Kimiko; Agata, Hideki; Ohshima, Hiroyuki

doi:10.1006/jcis.2000.7084

Cited by 25 publications

(12 citation statements)

References 14 publications

(22 reference statements)

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“…[36] Electrokinetic studies also manifest that the effective charge density of poly-(NIPAAm) varies with temperature. [39] The variation is proposed to be caused by the structural changes of the polymer chains and water molecules in the hydrogels.…”

Section: Effective Charge Densitymentioning

confidence: 99%

Modeling Investigation of Hydrogel Volume Transition

Chen

et al. 2004

Macro Theory & Simulations

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Summary: This paper provides an overview of the latest development in modeling and simulation of volume transition behaviors of hydrogels with models at both macroscopic and molecular levels. Energy conservation law, mass conservation law and momentum conservation law provide good starting points for developing models for hydrogel volume transition. Thermodynamic models, transport models, multiphasic mixture theory and molecular simulation are discussed. Thermodynamic models provide qualitative description of equilibrium volume transition of hydrogels. Both transport models and multiphasic mixture theory can predict transient and equilibrium volume transition of hydrogels. Molecular simulation provides mechanistic understanding of hydrogel volume transition. Several key parameters are summarized for future model development.

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Section: Effective Charge Densitymentioning

confidence: 99%

Modeling Investigation of Hydrogel Volume Transition

Chen

et al. 2004

Macro Theory & Simulations

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“…[13][14][15] Otherwise, pH sensitive copolymer microgels based on poly(methyl methacrylate), polystyrene, containing poly(methacrylic acid), poly(2-vinyl pyridine) have also been studied. [16][17][18] However, pH and thermo-sensitive microgels based on poly(4-vinyl pyridine, P4VP) have not been synthesized and studied.…”

mentioning

confidence: 99%

pH and Temperature-sensitive Behaviors of Poly(4-vinyl pyridine-co-N-isopropyl acrylamide) Microgels

Kim

Vincent

2005

Polym J

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ABSTRACT:Poly(4VP-co-NIPAM) microgels were prepared from 4-vinyl pyridine (4VP) and N-isopropyl acrylamide (NIPAM) with methylene-bis-acrylamide (MBAm) as a cross-linking agent using partially quarternized poly(4-vinyl pyridine) as emulsifier, which is a special emulsion polymerization method.The morphology and hydrodynamic diameter of the microgel particles were characterized by TEM and photon correlation spectroscopy (PCS). The dependence of pH and temperature of the copolymer microgel particles were investigated and the influence of the KCl concentration in the microgel dispersion was observed.Hydrodynamic diameters of the microgel particles were drastically increased below pH 5 and those of the microgel particles were depended on temperature and KCl concentration in the microgel dispersion. The dependence of pH and temperature on the microgel particles were affected by molar ratio of 4VP/NIPAM. The cross-linked copolymer microgels composed of 4VP/NIPAM ratio of 1/9, exhibited broad shrinking transition. The swelling behavior for the microgel dispersion was much sensitive to the KCl concentration in the microgel dispersion at elevated temperature. [DOI 10.1295/polymj.37.565] KEY WORDS Emulsion Polymerization / Poly(4VP-co-NIPAM) Microgels / pH/Temperaturesensitive Microgels / Swelling/Deswelling Behavior / Colloidal Particles / Polymer hydrogels and microgels have a wide range of potential application in biotechnology and biomedical field. Therefore, various polymer hydrogels and microgels have been characterized where the volume change can be induced by pH, temperature, ionic strength, and electric field of the polymer matrix.

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“…Inverse suspension polymerization of spherical hydrogels has been studied less often than normal suspension polymerization, especially with respect to thermosensitive polymers 21–24. In previous studies paraffin oil, dichloromethane, and xylene were used for the continuous phase.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of thermosensitive beads with macroporous structures

Wang

Zhu

2003

J of Applied Polymer Sci

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Thermosensitive copolymers of poly(N-isopropyl acrylamide)-co-2-hydroxyethyl methacrylate (NIPAco-HEMA) macroporous resins were synthesized in the form of beads by inverse suspension polymerization. The copolymerization was carried out in aqueous solutions of the comonomers dispersed by cyclohexane with stabilizers. A series of resins with different molar ratios of NIPA : HEMA, and different crosslinking degrees was obtained. The compositions of the copolymers were determined by elemental analysis. The results showed that the content of HEMA in a copolymer was higher than that of the corresponding feed mixture from which the copolymer was made. IR spectra also confirmed the structure of the copolymers. The porous parameters such as true densities, apparent densities, pore volumes, and porosities of the resins were measured by means of pycnometry. The determination of equilibrium swelling ratios and measurement of differential scanning calibration indicated that the resins exhibited thermosensitivity in aqueous solutions. Finally, the loading of hydroxyl groups was determined by titration. The resins have potential applications as supports in solid-phase synthesis after being functionalized.

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Dependence of Temperature-Sensitivity of Poly(N-isopropylacrylamide-co-acrylic acid) Hydrogel Microspheres upon Their Sizes

Cited by 25 publications

References 14 publications

Modeling Investigation of Hydrogel Volume Transition

Modeling Investigation of Hydrogel Volume Transition

pH and Temperature-sensitive Behaviors of Poly(4-vinyl pyridine-co-N-isopropyl acrylamide) Microgels

Preparation and characterization of thermosensitive beads with macroporous structures

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