Anomalous compressibility of N-isopropylacrylamide gels near the volume phase transition temperature

Kato, Eiji; Kitada, Tadayoshi; Nakamoto, Chikanobu

doi:10.1021/ma00059a040

Cited by 21 publications

(22 citation statements)

References 3 publications

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“…We have previously investigated pressure-induced changes in protein structure and function in several examples . PNIPAM derivatives have been shown to undergo pressure-induced transitions, both in solution and in gel form …”

mentioning

confidence: 99%

Effects of Pressure on the Behavior of the Thermoresponsive Polymer Poly(N-vinylisobutyramide) (PNVIBA)

Kunugi¹,

Takano²,

Tanaka³

et al. 1997

Macromolecules

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mentioning

confidence: 99%

Effects of Pressure on the Behavior of the Thermoresponsive Polymer Poly(N-vinylisobutyramide) (PNVIBA)

Kunugi¹,

Takano²,

Tanaka³

et al. 1997

Macromolecules

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“…1, Table I). UV-cure is advantageous versus free radical cure crosslinking 6, 49–50 as it involves shorter times and can be done at lower temperatures. 51–53 The efficacy of UV-cure was confirmed by Soxhlet extraction (CH 2 Cl 2 , 12 hr) of hydrogels containing 4 wt% nanoparticles ( f ) and pure PNIPAAm hydrogel ( a ) which both exhibited no detectable weight loss (<0.1 wt%).…”

Section: Resultsmentioning

confidence: 99%

Thermoresponsive Nanocomposite Hydrogels: Transparency, Rapid Deswelling and Cell Release

Hou

Fei

Burkes

et al. 2011

j biomat tissue engng

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Thermal modulation reversibly switches poly(N-isopropylacrylamide) (PNIPAAm) hydrogels between a water-swollen and a deswollen state which is useful for a variety of biomedical applications. The utility and efficiency of PNIPAAm hydrogels requires tailoring their rate of deswelling/reswelling, mechanical properties and/or optical clarity. In the current work, we prepared novel thermoresponsive nanocomposite hydrogels comprised of a PNIPAAm hydrogel matrix and polysiloxane colloidal nanoparticles (~54 nm ave. diameter) via in situ photopolymerization of aqueous solutions of NIPAAm monomer, N,N′-methylenebisacrylamide (BIS, crosslinker), photoinitiator and 0.5–4.0 wt% polysiloxane nanoparticles (wt% solids of nanoparticles with respect to NIPAAm weight) at ~7 °C. At these nanoparticle concentrations, the nanocomposite hydrogels were more optically transparent versus those prepared with analogous larger nanoparticles (~219 nm ave. diameter). The volume phase transition temperature (VPTT) of the nanocomposite hydrogels was conveniently unaltered versus that of the pure PNIPAAm hydrogel. Incorporation of nanoparticles caused enhancement in modulus as well as the extent and rate of deswelling. When cooled from 37 °C to 25 °C, mouse smooth muscle precursor cells (10T1/2) were effectively detached from nanocomposite hydrogel surfaces due to hydrogel swelling.

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“…The results indicate another inhomogeneity newly introduced into a normal network. However, the hydrostatic pressure effect on a swollen NIPA gel has clarified that the swelling volume decreases with increasing pressure 37–39. This effect is explained by the dehydration around hydrophobic portions of NIPA segments.…”

Section: Resultsmentioning

confidence: 99%

Kinetics of the volume phase transition in poly(n‐isopropylacrylamide) gels prepared under high pressure

Kitada

2001

J. Polym. Sci. A Polym. Chem.

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New poly(N‐isopropylacrylamide) gels were prepared under high pressure (ca. 200 MPa) during gelation. The preparation‐pressure dependence of the deswelling speed of the gels was measured with a conventional T‐jump method. The deswelling time of a gel rod 2.2 mm in diameter prepared at 193 MPa was about 200 s, 1000 times faster than that of a homogeneous poly(N‐isopropylacrylamide) gel. Moreover, the collective diffusion coefficient, the thermal fluctuation, and the ensemble‐average intensity of the swollen gel networks were obtained with dynamic light scattering measurements. Both the enthalpy and entropy of the gels were estimated from equilibrium swelling curves with the Flory–Huggins interaction parameter evaluated with mean field theory based on the Flory‐type of the Gibbs free‐energy formula. It was found that the networks of the gels had an inhomogeneous structure newly introduced by the preparation pressure. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2315–2325, 2001

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Anomalous compressibility of N-isopropylacrylamide gels near the volume phase transition temperature

Cited by 21 publications

References 3 publications

Effects of Pressure on the Behavior of the Thermoresponsive Polymer Poly(N-vinylisobutyramide) (PNVIBA)

Effects of Pressure on the Behavior of the Thermoresponsive Polymer Poly(N-vinylisobutyramide) (PNVIBA)

Thermoresponsive Nanocomposite Hydrogels: Transparency, Rapid Deswelling and Cell Release

Kinetics of the volume phase transition in poly(n‐isopropylacrylamide) gels prepared under high pressure

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