Thermal response of low molecular weight poly-(N-isopropylacrylamide) polymers in aqueous solution

Pamies, Ramón; Zhu, Kaizheng; Kjøniksen, Anna–Lena; Nyström, Bo

doi:10.1007/s00289-008-0029-4

Cited by 109 publications

(162 citation statements)

References 47 publications

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“…This concentration dependence of the LCST is in agreement with measurements on PNIPAM homopolymer samples. [7,10,11] In this measurement, the solution remains transparent at 34 8C, and turns to turbid at 35 8C. As discussed above, an R h value of %3 nm was obtained for P 137 N 3 single polymer chains in water.…”

Section: P X F 9 In Aqueous Solutionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10] However, the effect of polymer molar mass of PNIPAM on the LCST has been a controversial topic. Some studies find a molar mass dependence of the LCST, [7][8][9][10][11] whereas other reports claim an independence of the LCST. [3,12,13] Naturally, it can be assumed that there is a strong molar mass effect when using oligomers of PNIPAM in water that levels off when high molar masses of PNIPAM are used.…”

Section: Introductionmentioning

confidence: 99%

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Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Water^a

Kyeremateng

Fuchise

et al. 2009

Macro Chemistry & Physics

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Two hydrophobically modified PNIPAM semitelechelics PxF9 were prepared by “clicking” PNIPAM containing an azide endgroup (PxN3) with nonadecafluoro‐1‐decyl hex‐5‐ynoate (F9). Micelles of PxF9 in water with a core of F9‐segments and a PNIPAM corona were detected by dynamic light scattering and by 1H and 19F NMR spectroscopy below the LCST. Just below the LCST, the PNIPAM chains start to collapse onto the F9 core followed by aggregation of several collapsed micelles to large particles in the range of ≈110 nm. The F9 segments shifted the LCST to lower temperatures when comparing PxN3 with PxF9. The existence of micelles in PxF9 solutions also improved the reversibility of the LCST behavior as measured by DSC.

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Section: P X F 9 In Aqueous Solutionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Water^a

Kyeremateng

Fuchise

et al. 2009

Macro Chemistry & Physics

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“…It provides data regarding the hydrodynamic radii, which have been carefully described in previous studies [42,43]. Here, the particle size changes may indicate the effect of performed treatments.…”

Section: Dls Investigationmentioning

confidence: 99%

Universal approach of cellulose fibres chemical modification result analysis via commonly used techniques

2018

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This article considers the modification of cellulose fibres with the use of vinyltrimethoxysilane and maleic anhydride as substances to improve the wettability of the additive in the hydrophobic polymer matrix. The stress is put on the possible ways of modification impact investigation and its description. Effects of the treatment are analysed using Fourier transform infrared spectroscopy, which reveal the presence of new moieties on the cellulose surface, e.g. C=C bonds, C=O and Si-C groups, while dynamic light scattering investigation revealed an increase in the hydrodynamic radii of the molecules which was maximized in the case of modification with the use of maleic anhydride. Furthermore, thermal properties were defined with differential scanning calorimetry and thermogravimetric analysis. Some variations within the process of samples thermal degradation are observed-thermal stability of the specimen modified with maleic anhydride is the highest. The presented approach of combined fibre modification analysis techniques, being a scientific novelty, allows to confirm the treatment impact on cellulose properties at many levels. Graphical abstractKeywords Cellulose · Maleic anhydride · Vinyltrimethoxysilane

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“…The same was observed for the PNIPAAm block. Nyström et al reported on the correlation of polymer length with Tc for PNIPAAm [44]. With increase of the number of repeating units from 47 to 71, Tc decreased from 36.9 to 32.2 °C.…”

Section: Thermal Phase Transition Behavior Of Star-like Pnipaam Homo mentioning

confidence: 99%

Synthesis of β-cyclodextrin-Based Star Block Copolymers with Thermo-Responsive Behavior

et al. 2015

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Star polymers are one example of three-dimensional macromolecules containing several arms with similar molecular weight connected to a central core. Due to their compact structure and their enhanced segment density in comparison to linear polymers of the same molecular weight, they have attracted significant attention during recent years. The preparation of block-arm star copolymers with a permanently hydrophilic block and an "environmentally" sensitive block, which can change its nature from hydrophilic to hydrophobic, leads to nanometer-sized responsive materials with unique properties. These polymers are able to undergo a conformational change or phase transition as a reply to an external stimulus resulting in the formation of core-shell nanoparticles, which further tend to aggregate. Star-shaped copolymers with different cores were synthesized via atom transfer radical polymerization (ATRP). The core-first method chosen as synthetic strategy allows good control over the polymer architecture. First of all the multifunctional initiators were prepared by esterification reaction of the hydroxyl groups with 2-chloropropionyl chloride. Using β-cyclodextrin as core molecules, which possess a well-defined number of functional groups up to 21, allows defining the number of arms per star polymer. In order to prepare stimuli-responsive multi-arm copolymers, containing a stimuli-responsive (poly(N-isopropylacrylamide) (PNIPAAm)) and a non-responsive block (poly(N,N-dimethylacrylamide) (PDMAAm)), consecutive ATRP was carried out. The polymers were characterized intensively using NMR spectroscopy OPEN ACCESSPolymers 2015, 7 922 and size exclusion chromatography (SEC), whereas the temperature-depending aggregation behavior in aqueous solution was determined via turbidimetry and differential scanning calorimetry (DSC).

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Thermal response of low molecular weight poly-(N-isopropylacrylamide) polymers in aqueous solution

Cited by 109 publications

References 47 publications

Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Water^a

Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Water^a

Universal approach of cellulose fibres chemical modification result analysis via commonly used techniques

Synthesis of β-cyclodextrin-Based Star Block Copolymers with Thermo-Responsive Behavior

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Thermal response of low molecular weight poly-(N-isopropylacrylamide) polymers in aqueous solution

Cited by 109 publications

References 47 publications

Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Watera

Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Watera

Universal approach of cellulose fibres chemical modification result analysis via commonly used techniques

Synthesis of β-cyclodextrin-Based Star Block Copolymers with Thermo-Responsive Behavior

Contact Info

Product

Resources

About

Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Water^a

Aggregation Behavior of Poly(N‐isopropylacrylamide) Semitelechelics with a Perfluoroalkyl Segment in Water^a