Synthesis and Thermo-responsive Properties of Amino Group Terminated Poly(N-isopropylacrylamide) and Sodium Alginate-g-Poly(N-isopropylacrylamide)

이은주,; 김영호,

doi:10.7317/pk.2013.37.4.539

Cited by 4 publications

(2 citation statements)

References 25 publications

(17 reference statements)

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“…ι-Carrageenan is comparable to DNA with respect to the linear charge density in the completely extended conformation . In aqueous solutions of several univalent electrolytes, ι-carrageenan takes a helix conformation at sufficiently low temperatures. − The stability of the helix conformation of ι-carrageenan depends very strongly on the concentration of a background electrolyte. ,, For example, when the KCl concentration varies from 0.01 to 1.2 M the helix–coil transition temperature of ι-carrageenan increases from 20 to 84 °C while maintaining a constant transition enthalpy . These tendencies suggest an entropic driving force of the salt effect on the stability of the helix conformation of ι-carrageenan.…”

Section: Introductionmentioning

confidence: 99%

Conformational Energetics of Interpolyelectrolyte Complexation between ι-Carrageenan and Poly(methylaminophosphazene) Measured by High-Sensitivity Differential Scanning Calorimetry

et al. 2011

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The interaction of poly(methylaminophosphazene) hydrochloride (PMAP·HCl) of varying degrees of ionization (f) with the potassium salt of ι-carrageenan was studied by high-sensitivity differential scanning calorimetry at a KCl concentration of 0.15 M, which is included for the purpose of stabilizing the helix conformation of the polysaccharide up to 55 °C. The conditions of strong (pH 3.8, I = 0.15), moderate (pH 7.4, I = 0.15), and weak (pH 7.4, I = 0.25) electrostatic interactions of the polyelectrolytes were considered. The thermodynamic parameters of the helix-coil transition of ι-carrageenan were determined as a function of the polycation/polyanion ratio. We show that the interpolyelectrolyte reaction between PMAP·HCl and ι-carrageenan results in a complete unfolding of the polysaccharide helix under conditions of strong electrostatic interaction and increases its stability under conditions of medium and weak electrostatic interactions. The formation of stoichiometric PMAP-carrageenan interpolyelectrolyte complexes proceeded via a cooperative mechanism at pH 3.8 (f = 0.5) and pH 7.4 (f = 0.2) at an ionic strength of 0.15. In contrast, the complexation at pH 7.4 and an ionic strength of 0.25 could be considered to be a consecutive competitive binding of charged units of poly(methylaminophosphazene) to the oppositely charged polysaccharide matrix in the helix or coil conformation. Binding constants of the polycation to the helix and coil forms of ι-carrageenan were estimated. They revealed a preferential binding of the polycation to the helix form of the polysaccharide.

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Section: Introductionmentioning

confidence: 99%

Conformational Energetics of Interpolyelectrolyte Complexation between ι-Carrageenan and Poly(methylaminophosphazene) Measured by High-Sensitivity Differential Scanning Calorimetry

et al. 2011

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“…Thus, each monosaccharide unit in the ideal polysaccharide carries one sulfate group, and therefore ι‐carrageenan behaves in aqueous solution as a highly charged polyanion in the extended confirmation 3. It is known that the polysaccharide has a double helix conformation in the solid phase by X‐ray Diffraction data while in calcium salt it is converted to a three‐fold right‐handed double helix with parallel strands 4–6. In solution, ι‐carrageenan is reversibly transformed from an ordered to a disordered conformation.…”

Section: Introductionmentioning

confidence: 99%

Study of thermal phase transitions in iota carrageenan gels via fluorescence technique

Tarı¹,

Kara²,

Pekcan³

2011

J of Applied Polymer Sci

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The effect of carrageenan concentration on thermal phase transitions of the iota carrageenan gels was investigated by using fluorescence technique. During heating and cooling processes, scattered light, I sc , and fluorescence intensity, I p , were monitored against temperature to investigate phase transitions. Transition temperatures from the derivative of the transition paths were determined. Two regions were observed during the heating and cooling processes. At the first step of the heating, dimers were converted into double helix by undergoing dimer to double helix (d-h) transition. At the higher tem-perature region, double helix to coil (h-c) transition took place. During the cooling process, these transitions are arranged in the order of coil to double helix (c-h) and double helix to dimer (h-d). A hysteresis was observed between (h-d) and (d-h) transitions. The critical gel fraction exponents, b, were found to be independent of the system by indicating that they all fall into the same universality class.

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UV Photoinitiated Temperature-Sensitive Modification of Polypropylene Grafted with Poly(N-isopropylacrylamide)

Zheng

Xiong

et al. 2022

Polym. Sci. Ser. B

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Synthesis and Thermo-responsive Properties of Amino Group Terminated Poly(N-isopropylacrylamide) and Sodium Alginate-g-Poly(N-isopropylacrylamide)

Cited by 4 publications

References 25 publications

Conformational Energetics of Interpolyelectrolyte Complexation between ι-Carrageenan and Poly(methylaminophosphazene) Measured by High-Sensitivity Differential Scanning Calorimetry

Conformational Energetics of Interpolyelectrolyte Complexation between ι-Carrageenan and Poly(methylaminophosphazene) Measured by High-Sensitivity Differential Scanning Calorimetry

Study of thermal phase transitions in iota carrageenan gels via fluorescence technique

UV Photoinitiated Temperature-Sensitive Modification of Polypropylene Grafted with Poly(N-isopropylacrylamide)

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