A quantitative analyses of the viscometric data of the coil-to-globule and globule-to-coil transition of poly(N-isopropylacrylamide) in water

Yang, Hu; Cheng, Rongshi; Wang, Zhiliu

doi:10.1016/j.polymer.2003.09.008

Cited by 30 publications

(32 citation statements)

References 19 publications

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“…For both approaches, poly(divinylbenzene) (pDVB80) particles were prepared by precipitation polymerization, having diameters of 1.3 µm. These microspheres have a thin surface layer consisting of lightly cross-linked and swellable poly (divinyl benzene) 31 and contain vinyl groups on their surfaces which are accessible for modification, i.e. direct surface modification via "grafting to" techniques.…”

Section: Resultsmentioning

confidence: 99%

Surface Modification of Poly(divinylbenzene) Microspheres via Thiol−Ene Chemistry and Alkyne−Azide Click Reactions

et al. 2009

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We report the functionalization of cross-linked poly(divinylbenzene) (pDVB) microspheres using both thiol-ene chemistry and azide-alkyne click reactions. The RAFT technique was carried out to synthesize SH-functionalized poly(N-isopropylacrylamide) (pNIPAAm) and utilized to generate pNIPAAm surface-modified microspheres via thiol-ene modification. The accessible double bonds on the surface of the microspheres allow the direct coupling with thiol-end functionalized pNIPAAm. In a second approach, pDVB microspheres were grafted with poly(2-hydroxyethyl methacrylate) (pHEMA). For this purpose, the residual double bonds on the microspheres surface were used to attach azide groups via the thiol-ene approach of 1-azido-undecane-11-thiol. In a second step, alkyne endfunctionalized pHEMA was used to graft pHEMA to the azide-modified surface via click-chemistry (Huisgen 1,3-dipolar cycloaddition). The surface-sensitive characterization methods X-ray photoelectron spectroscopy, scanning-electron microscopy and FT-IR transmission spectroscopy were employed to characterize the successful surface modification of the microspheres. In addition, fluorescence microscopy confirms the presence of grafted pHEMA chains after labeling with Rhodamine B.

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Section: Resultsmentioning

confidence: 99%

Surface Modification of Poly(divinylbenzene) Microspheres via Thiol−Ene Chemistry and Alkyne−Azide Click Reactions

et al. 2009

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“…Polymers of Nisopropylacrylamide (NIPAAM) are a well-known example of such a system with LCST. A number of different reports on temperature-responsive behaviour of NIPAAM homopolymer [7][8][9] as well as copolymers with cationic, [10] anionic [11,12] and non-ionic monomers [13] can be found in the literature. The other temperature-sensitive polymers, which are not based on NIPAAM, include poly(vinyl methyl ether), some cellulose ethers, poly(N-vinylcaprolactame), poly(2-ethyl-2-oxazoline), etc.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Responsive Water‐Soluble Copolymers Based on 2‐Hydroxyethyl Acrylate and Butyl Acrylate

Mun¹,

Nurkeeva²,

Beissegul³

et al. 2007

Macro Chemistry & Physics

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Amphiphilic copolymers have been synthesised by free radical copolymerisation of 2‐hydroxyethyl acrylate with butyl acrylate, the reactivity ratios of which indicate practically equal reactivity. The copolymers containing less than 30 mol‐% of BA were soluble in water and exhibited a LCST in aqueous solutions. It was found that the interaction between these copolymers and poly(acrylic acid) in aqueous solutions resulted in the formation of interpolymer complexes stabilised by hydrogen bonds and hydrophobic interactions. This interaction was significantly affected by solution pH and led to modification of the temperature‐responsive behaviour of the copolymers.magnified image

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“…The best fit of the theoretical kinetic curve with the experimental data will be obtained if the chosen value of k 4 is less than the others, as shown in Figure 6. This means that the reverse reaction (globule-coil transition) should be retarded, and the experimental facts 15,16,18 confirmed this prediction. Thus, we can conclude that the coil-globule transition of PNIPAM in aqueous solution is essentially a two-stage process.…”

Section: Time-temperature Superposition Applied To Polymer Kineticsmentioning

confidence: 63%

“…PNIPAM 4 -6 is a kind of thermosensitive polymer in aqueous solution; the transition from a coil to a globule takes place when the temperature rises to its lower critical solution temperature at around 32°C. We studied the coil-globule transition and the reverse process globule-coil transition of single chain PNIPAM by viscometry 15,16 and differential refractometry. 17 It was shown that a mechanism involving two steps probably was still simplified because a hydration-dehydration process occurs simultaneously during the transition.…”

Section: Applicationmentioning

confidence: 99%

“…17 It was shown that a mechanism involving two steps probably was still simplified because a hydration-dehydration process occurs simultaneously during the transition. 17 To reillustrate this viewpoint, we use the timetemperature super position principle to treat the intrinsic viscosity data at different temperatures reported earlier 15,16 as an application example. Figure 1 shows the variation of the intrinsic viscosity of PNI-PAM in aqueous solution with the temperature.…”

Section: Applicationmentioning

confidence: 99%

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Application of time–temperature superposition principle to polymer transition kinetics

Cheng

Yang

2005

J of Applied Polymer Sci

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ABSTRACT:The time-temperature equivalence equation is deduced simply in view of the transition kinetics of a polymer. The independent variables time and temperature are separated in the two sides of the resulting equation. Thus, a physical property of the polymer, which is temperature dependent, can be matched with the theoretical calculated curve from a supposed model of transition kinetics in which only time is involved as the independent variable. By comparing different models, one may judge which model is probably more correct. The procedure of data fitting is described. As an application example, the measured viscosity data at different temperatures for the coil-globule transition of poly(N-isopropylacrylamide) in aqueous solution is tested to judge its transition mechanism. A transition mechanism involving a two-stage reversible reaction fits the experimental data in a satisfactory way.

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A quantitative analyses of the viscometric data of the coil-to-globule and globule-to-coil transition of poly(N-isopropylacrylamide) in water

Cited by 30 publications

References 19 publications

Surface Modification of Poly(divinylbenzene) Microspheres via Thiol−Ene Chemistry and Alkyne−Azide Click Reactions

Surface Modification of Poly(divinylbenzene) Microspheres via Thiol−Ene Chemistry and Alkyne−Azide Click Reactions

Temperature‐Responsive Water‐Soluble Copolymers Based on 2‐Hydroxyethyl Acrylate and Butyl Acrylate

Application of time–temperature superposition principle to polymer transition kinetics

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