Thermoreversible gelation of isotactic-rich poly(<i>N</i>-isopropylacrylamide) in water

Nakano, Shinya; Ogiso, Takao; Kita, R.; Shinyashiki, Naoki; Yagihara, Shin; Yoneyama, Mitsuru; Katsumoto, Yukiteru

doi:10.1063/1.3637943

Cited by 43 publications

(69 citation statements)

References 31 publications

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“…18−21 For isotacticity-rich PNiPA homopolymer, the solubility in water decreases and the transition temperature slightly decreases with increasing isotacticity. 19,20 The coil-to-globule transition of PNiPA and PdEA in water is distinctly reflected in the IR spectra especially in the CO stretching (amide I) and C−H stretching band regions. 22−25 Two amide I bands are apparently observed for PNiPA and PdEA in aqueous solution and the higher wavenumber band increases with increasing temperature through the coil-toglobule transition.…”

Section: ■ Introductionmentioning

confidence: 99%

Hydration States of Poly(N-isopropylacrylamide) and Poly(N,N-diethylacrylamide) and Their Monomer Units in Aqueous Solutions with Lower Critical Solution Temperatures Studied by Infrared Spectroscopy

Hashimoto

Nagamoto²,

Maruyama³

et al. 2013

Macromolecules

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The coil-to-globule transition of poly(N-isopropylacrylamide) (PNiPA) and poly(N,N-diethylacrylamide) (PdEA) in aqueous solutions has recently received substantial interest in its drastic change in the hydration state from a hydrated random coil to a hydrophobic globule for practical applications: drug delivery and tissue engineering. In this report, the hydration states of PNiPA and PdEA in aqueous solutions were investigated by IR spectroscopy in the amide I, N−H and C−H stretching band regions as compared with those of their repeat units, N-isopropylpropionamide (NiPP) and N,N-diethylpropylacrylamide (dEP) in aqueous and cyclohexane solutions in combined with their phase diagrams. The IR spectral changes in the amide I and C−H stretching band regions of Nalkylamides and N,N-dialkylamides including NiPP and dEP in aqueous solutions with varying concentration was characteristic due to different amide−amide interaction; the amide−amide interaction for N-alkylamide (CO···H−N hydrogen bond) is stronger than that for N,N-dialkylamide (dipolar interaction). It is found that almost all amide groups of PNiPA in aqueous solution forms the intramolecular CO···H−N hydrogen bond even in the coil state and that the amide group of PNiPA is less hydrated than that of PdEA in spite of the similar degree of hydration to alkyl groups. The IR spectral changes in the amide I and C−H stretching band regions of PNiPA and PdEA in aqueous solutions with heat are ascribed to the dehydration of the amide and alkyl groups from the coil state to the globule one.

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Section: ■ Introductionmentioning

confidence: 99%

Hydration States of Poly(N-isopropylacrylamide) and Poly(N,N-diethylacrylamide) and Their Monomer Units in Aqueous Solutions with Lower Critical Solution Temperatures Studied by Infrared Spectroscopy

Hashimoto

Nagamoto²,

Maruyama³

et al. 2013

Macromolecules

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“…The correlation function g (1) (t) has no characteristic time and exhibits a power-law behavior at the gelation point. Consequently, the three-dimensional network structure develops on the macroscopic scale and the density (concentration) fluctuation begins to have a self-similar nature, as has been observed in various gelling systems [24][25][26][29][30][31][32]:…”

Section: Dynamic Light Scattering (Dls) Measurementsmentioning

confidence: 82%

“…The interaction between, or aggregation of, scattering molecules can be inferred from their diffusion coefficients [23]. Moreover, reactions taking place during the gelling process can be interpreted at the molecular level [24][25][26]. Tanaka et al have reported the denaturation and aggregation of HEWL molecule in an alcohol solution by using DLS measurement.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of amyloid-like aggregation and gel formation of hen egg-white lysozyme in highly concentrated ethanol solution

et al. 2017

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We investigated the mechanisms of amyloidlike aggregation and gel formation in hen egg-white lysozyme (HEWL) in a mixed solvent comprising 90% v/v ethanol in water using dynamic light scattering (DLS) and circular dichroism CD. The mechanism of HEWL in ethanol aqueous solution is interpreted into three stages as: (I) denaturation of HEWL; (II) elongation of amyloid fibrils composed of β-sheet-rich HEWL by lateral aggregation; and (III) gel formation due to the creation of junctions in amyloid fibrils. The transformation of sol to gel can be confirmed by: (1) the oscillation behavior and the rapid increase in the intensity of scattered light; (2) the power-law behavior of the correlation function of scattered light g (2) (t); (3) the appearance of a long-time tail in the distribution function of the decay time G(τ); and (4) the beginning of the reduction in initial amplitude in g (2) (t). The gelation rate was strongly dependent on the protein concentration. The estimated rod length of the amyloid fibrils increased significantly over time. Scanning electron microscopy (SEM) performed on the formation of fibrils in the HEWL gels revealed that the structure was highly heterogeneous, with areas characterized by dense fiber networks interspersed with loose network areas.

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“…Eine systematische Studie des Einflusses von m auf das Entmischungsverhalten findet sich bei Ray et al [21] für PNIPAM-Proben, die durch reversible Additions-Fragmen Nakano et al [36] stellten interessanterweise fest, dass das Erhitzen einer reich isotaktischen PNIPAM-Lçsung (m = 64 %) nicht nur zu einer verstärkten Tr übung,s ondern auch zu einem Sol-Gel-Übergang,d er sich anhand der Sinkgeschwindigkeit einer Nickelkugel nachweisen ließ. Für w > 0.017 wiesen sie aufgrund der einsetzenden Trübung einen Sol-Gel-Übergang unterhalb von T dem nach.…”

Section: Taktizitätunclassified

“…Einfluss des Mesodiaden-Gehalts, m,auf die Entmischungstemperatur T dem ,a ls Funktion der Gewichtsfraktion w.D ie Entmischungstemperatur T dem wurde hierbei aus dem Verhalten der ersten Ableitung, [34] oder auch mithilfe des Kriteriums eines 50 %igen Einbruchs der Transmission [36] aus den Transmissionskurven erhalten. In den meisten der im Folgenden diskutierten Experimente ist Av on Bv erschieden.…”

Section: Endgruppen-effekteunclassified

Poly(N‐isopropylacrylamid)‐Phasendiagramme: 50 Jahre Forschung

2015

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Im Jahr 1968 publizierten Heskins und Guillet die erste systematische Studie über das Phasendiagramm von Poly(N‐isopropylacrylamid) (PNIPAM), einem zu jener Zeit “jungen Polymer”, das erstmalig 1956 synthetisiert worden war. Seitdem ist PNIPAM zu einem führenden Vertreter der wachsenden Familie temperatur‐ und reizempfindlicher Polymere geworden. Seine thermische Antwort ist fraglos durch sein Phasenverhalten begründet. Nach nunmehr 50 Jahren Forschung zeichnet sich noch immer kein einheitliches, quantitatives Bild seines Verhaltens ab. In diesem Aufsatz treten wir eine Reise zu den beobachteten Phasendiagrammen an. Wir kommentieren theoretische Überlegungen zu den möglichen Ursachen der dabei offensichtlich werdenden Unterschiede. Dabei ist es unser Ziel, nach wie vor offene Fragen auf diesem altehrwürdigen Gebiet vor Augen zu führen.

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Thermoreversible gelation of isotactic-rich poly(N-isopropylacrylamide) in water

Cited by 43 publications

References 31 publications

Hydration States of Poly(N-isopropylacrylamide) and Poly(N,N-diethylacrylamide) and Their Monomer Units in Aqueous Solutions with Lower Critical Solution Temperatures Studied by Infrared Spectroscopy

Hydration States of Poly(N-isopropylacrylamide) and Poly(N,N-diethylacrylamide) and Their Monomer Units in Aqueous Solutions with Lower Critical Solution Temperatures Studied by Infrared Spectroscopy

Dynamics of amyloid-like aggregation and gel formation of hen egg-white lysozyme in highly concentrated ethanol solution

Poly(N‐isopropylacrylamid)‐Phasendiagramme: 50 Jahre Forschung

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