Solvents effect on the physical properties of semi-dilute poly(N-isopropyl acryl amide) solutions

Yu, T. Leon; Lu, Wen-Chi; Liu, Wen-Horng; Lin, Hsiu-Li; Chiu, Chih‐Hao

doi:10.1016/j.polymer.2004.05.074

Cited by 17 publications

(12 citation statements)

References 25 publications

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“…Through DLS, Yu et al . found two correlation length modes in 5.0 wt % PNIPAM ( M w = 3.22 × 10 5 g/mol) aqueous solutions below LCST . Pamies et al .…”

Section: Resultsmentioning

confidence: 97%

Concentration effect on aggregation and dissolution behavior of poly(N‐isopropylacrylamide) in water

Yan

Huang²,

Zhang

et al. 2014

J of Applied Polymer Sci

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The concentration effect on aggregation and dissolution behavior of poly(N-isopropylacrylamide) (PNIPAM) in water was studied. Three concentration regimes with different phase behavior were identified by differential scanning calorimetry (DSC). Further optical, light-scattering, and rheological studies indicated that the appearance of different regimes arose from their corresponding solution structures below lower critical solution temperature (LCST): free chains and small clusters in regime I, large clusters in regime II, and a gel-like network in regime III. Different solution structures below LCST led to different phase-separated patterns formed above LCST: colloidal particles in regime I, large precipitate in regime II, and the sponge-like solid in regime III, which was well understood based on the overlapping parameter P. Different phase-separated patterns therefore resulted in different remixing behavior as observed by DSC. This work suggests that the swelling and collapse behavior of PNIPAM based hydrogels was controlled through the design of their phase-separated patterns, and therefore provided a way to develop high performance thermo-sensitive materials.

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“…Through DLS, Yu et al . found two correlation length modes in 5.0 wt % PNIPAM ( M w = 3.22 × 10 5 g/mol) aqueous solutions below LCST . Pamies et al .…”

Section: Resultsmentioning

confidence: 97%

Concentration effect on aggregation and dissolution behavior of poly(N‐isopropylacrylamide) in water

Yan

Huang²,

Zhang

et al. 2014

J of Applied Polymer Sci

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“…In particular, the mechanisms that govern the solvation of the PNIPAM chain in a mixed solvent of water and any short chain alcohol (e.g., methanol)termed cononsolvencyis far from being well understood . Albeit, at room temperature, both water and methanol are good solvents for the polymer, phase separation is encountered in a certain composition range of the solvent mixture. − …”

Section: Introductionmentioning

confidence: 99%

Solvent Dynamics in Solutions of PNIPAM in Water/Methanol Mixtures—A Quasi-Elastic Neutron Scattering Study

et al. 2016

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The solvent dynamics of concentrated solutions of poly(N-isopropylacrylamide) (PNIPAM, 25 wt %) in water/methanol mixtures (85:15 v/v) are measured with the aim of shedding light onto the cononsolvency effect. Quasi-elastic neutron scattering (QENS) with contrast variation has been carried out at temperatures below and above the cloud point by using in the first set of experiments the mixture H2O:d-MeOD (d-MeOD denotes fully deuterated methanol) as a solvent and in the second set of experiments the mixture D2O:MeOH (MeOH denotes methanol). As a reference, bulk H2O, bulk MeOH and the mixtures H2O:d-MeOD and D2O:MeOH (both 85:15 v/v) have been investigated as well. In the PNIPAM solution in H2O:d-MeOD, two water populations are identified, namely strongly and less strongly arrested water. At the cloud point, the former is partially released from PNIPAM. The diffusion coefficient of the latter one is similar to the one in the water/methanol mixture, and its residence time decreases at the cloud point. The PNIPAM solution in D2O:MeOH reveals similar dynamics to the one in H2O:d-MeOD which may reflect that the dynamics of MeOH near the PNIPAM chain is similar to the one of H2O. The similarity may, however, partially be due to H/D exchange between D2O and MeOH. In both PNIPAM solutions, the mean-square displacement of the PNIPAM chain decreases gradually above the cloud point.

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“…CLRP of NIPAM has been reported using nitroxide‐mediated radical polymerization (NMP),6–12 atom transfer radical polymerization (ATRP),7, 13, 14 reversible addition‐fragmentation chain transfer (RAFT) polymerization,7, 15–25 organotellurium‐mediated radical polymerization,26 and single electron transfer living radical polymerization 27. NIPAM is a solid at room temperature (mp = 60−63 °C), and is most commonly polymerized in solution, using benzene,9, 15, 28 alcohols,13, 27, 29 1,4‐dioxane,15, 16, 21, 22, 25 N , N ‐dimethylformamide (DMF),6, 8, 10, 11, 18, 26 anisole7, 14, or water23, 24 as solvents.…”

Section: Introductionmentioning

confidence: 99%

Chain transfer to solvent in the radical polymerization of N‐isopropylacrylamide

Sugihara

O’Connor

Zetterlund

et al. 2011

J. Polym. Sci. A Polym. Chem.

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Chain transfer to solvent has been investigated in the conventional radical polymerization and nitroxide‐mediated radical polymerization (NMP) of N‐isopropylacrylamide (NIPAM) in N,N‐dimethylformamide (DMF) at 120 °C. The extent of chain transfer to DMF can significantly impact the maximum attainable molecular weight in both systems. Based on a theoretical treatment, it has been shown that the same value of chain transfer to solvent constant, Ctr,S, in DMF at 120 °C (within experimental error) can account for experimental molecular weight data for both conventional radical polymerization and NMP under conditions where chain transfer to solvent is a significant end‐forming event. In NMP (and other controlled/living radical polymerization systems), chain transfer to solvent is manifested as the number‐average molecular weight (Mn) going through a maximum value with increasing monomer conversion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

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Solvents effect on the physical properties of semi-dilute poly(N-isopropyl acryl amide) solutions

Cited by 17 publications

References 25 publications

Concentration effect on aggregation and dissolution behavior of poly(N‐isopropylacrylamide) in water

Concentration effect on aggregation and dissolution behavior of poly(N‐isopropylacrylamide) in water

Solvent Dynamics in Solutions of PNIPAM in Water/Methanol Mixtures—A Quasi-Elastic Neutron Scattering Study

Chain transfer to solvent in the radical polymerization of N‐isopropylacrylamide

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