Effect of additives on phase transition of N-isopropylacrylamide gels

Inomata, Hiroshi; Goto, Shu-ichi; Otake, Katsuto; Saito, Shozaburo

doi:10.1021/la00038a064

Cited by 242 publications

(213 citation statements)

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“…This is followed by an investigation of the variation of the osmotic pressure of the gels as a function of added salt. The response of PNIPAM gels to ions follows closely that of uncross-linked PNIPAM solutions [19][20][21]. The findings are discussed in comparison with polyelectrolyte gels, a class of polymers that exhibits analogous volume phase transition behaviour in the presence of salt.…”

mentioning

confidence: 59%

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Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Manek

Tombácz

Geissler

et al. 2017

Period. Polytech. Chem. Eng.

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mentioning

confidence: 59%

“…The sensitivity of PNIPAM to various anions in the Hofmeister series [56] is well known [21,46]. Table 2 lists the effect of cations from various alkali and alkali earth metal chlorides on T onset and on ∆H and ∆S of the PNIPAM gel phase transition.…”

Section: Effect Of Ionsmentioning

confidence: 99%

Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Manek

Tombácz

Geissler

et al. 2017

Period. Polytech. Chem. Eng.

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“…It is generally believed that the salt ions interact with water molecules surrounding PNIPAM, leading to destabilize the hydrogen bondings between the polymer and water. [25][26][27] As a result, the PNIPAM-PNIPAM interactions become stronger than the water-PNIPAM interactions and the polymer molecules precipitate. We investigated the effects of sodium chloride and potassium chloride on the LCST and micelle formation of starEO-b-NIPAM.…”

Section: Resultsmentioning

confidence: 99%

Thermosensitive Block Copolymers Consisting of Poly(N-isopropylacrylamide) and Star Shape Oligo(ethylene oxide)

Lee¹,

Chang

2009

Bulletin of the Korean Chemical Society

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Thermosensitive block copolymers of ethylene oxide and N-isopropylacrylamide (NIPAM) were synthesized. A five armed star shape oligo(ethylene oxide) initiator with a cyclotriphosphazene core was prepared and used for the atom transfer radical polymerization (ATRP) of NIPAM. The lower critical solution temperatures (LCSTs) of the copolymers were 36 to 46 o C, higher than that of PNIPAM (32 o C), depending on their molecular weights. The copolymers were soluble in water below the LCSTs but formed micelles above the LCSTs. The thermosensitive micellization behaviors of the polymers were investigated by fluorescence spectroscopy. With increasing the temperature of an aqueous solution of P2 and pyrene above the LCST, the peak of 333 nm red-shifted to appear around 339 nm and its intensity increased significantly, indicating the micelle formation. The transfer of pyrene into the micelles was also confirmed by a confocal laser scanning microscope. The fluorescence image obtained from P2 in an aqueous pyrene solution exhibited a green emission resulting from the pyrene transferred into the micelles. Salt effects on the solubility of the copolymers in an aqueous solution were investigated. The LCST of P2 decreased sharply as the concentration of sodium chloride increased, while decreased slowly with potassium chloride.

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“…The decrease in the transmittance is explained by salting out of the thermoresponsive polymers. [17][18][19][20] Maximizing the difference in transmittance between the absence and presence of avidin improves the sensitivity of the assay. We chose the standard concentration of PBS for the following experiments because it produced the maximum difference in transmittance.…”

Section: Effect Of the Concentration Of Biotinylated Poly(acrylate) Amentioning

confidence: 99%

Thermal-induced Immuno-nephelometry Using Gold Nanoparticles Conjugated with a Thermoresponsive Polymer for the Detection of Avidin

et al. 2015

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Thermoresponsive immunonephelometry was achieved with biotinylated poly(acrylate) and thermoresponsive gold nanocomposites composed of 13-nm gold nanoparticles and thermoresponsive polymers containing triethylenetetramine and biotin groups. The avidin-biotin interaction was used to model an immunoreaction in order to demonstrate thermoresponsive immunonephelometry. In the absence of avidin, positively charged gold nanocomposites electrostatically interacted with biotinylated poly(acrylate) to form binary complexes, in which the charges canceled each other out. The charge cancelation resulted in the binary complexes precipitating when the solution was heated above the phase-transition temperature. However, adding avidin formed ternary sandwich complexes through the avidin-biotin interaction. The ternary complexes remained sufficiently soluble above the phase-transition temperature because of the spatial isolation of the positive and negative charges. The transmittance of the solution containing the thermoresponsive gold nanocomposites and biotinylated poly(acrylate) at 37 C increased as the avidin concentration increased. A sigmoidal profile was observed from 10 -6.5 to 10 -5.5 mol/L. The concentration of avidin spiked in bovine serum was determined by our method.

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Effect of additives on phase transition of N-isopropylacrylamide gels

Cited by 242 publications

References 0 publications

Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Thermosensitive Block Copolymers Consisting of Poly(N-isopropylacrylamide) and Star Shape Oligo(ethylene oxide)

Thermal-induced Immuno-nephelometry Using Gold Nanoparticles Conjugated with a Thermoresponsive Polymer for the Detection of Avidin

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