Erratum: The collapse transition of poly(styrene-b-(N-isopropyl acrylamide)) diblock copolymers in aqueous solution and in thin films

Troll, K.; Kulkarni, Abhijit; Wang, W.; Darko, Charles; Koumba, A. M. Bivigou; Laschewsky, André; Müller‐Buschbaum, Peter; Papadakis, Christine M.

doi:10.1007/s00396-010-2344-1

Cited by 3 publications

(2 citation statements)

References 43 publications

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“…We note both in Table . It is noteworthy here that in the case of PS- b -PNIPAM solution our DSC measurements point to T DSC values (27–28 °C) that are lower than the CP estimated by turbidimetry (31.6 °C); , however, they are within the temperature range where the structure of the micelles starts to change. , In contrast, for the PS- b -PMDEGA solution, the T DSC values (41–44 °C) are higher than the CP estimated by turbidimetry (40.0 °C). The breadth, Δ T breadth , of the transition, which can be defined as Δ T breadth = T end – T on , where T end denotes the temperature where the thermogram after the endothermic/exothermic peak merges again with the baseline or reaches the plateau value, is found to be about 11 °C for the PS- b -PNIPAM solution and 22 °C for the PS- b -PMDEGA solution, at the heating rate of 3 °C/min.…”

Section: Resultscontrasting

confidence: 60%

“…Regarding the PS- b -PNIPAM solution, previous synchrotron SAXS measurements and small-angle neutron scattering (SANS) measurements on concentrated solutions (30 wt % polymer) of the similar PS 50 - b -PNIPAM 160 diblock copolymer revealed thermoresponsive behavior different from that of the PS- b -PMDEGA solution. PS- b -PNIPAM forms core–shell micelles with a peculiar behavior around the CP: At temperatures up to 26 °C, the PNIPAM shell is swollen, however, less than expected for a good or a θ solvent.…”

Section: Resultsmentioning

confidence: 96%

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Comparative Investigation of the Thermoresponsive Behavior of Two Diblock Copolymers Comprising PNIPAM and PMDEGA Blocks

et al. 2018

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The thermoresponsive behavior of two diblock copolymers PS- b-PNIPAM and PS- b-PMDEGA, which both comprise a hydrophobic polystyrene (PS) block but different thermoresponsive blocks, also differing in length, poly( N-isopropylacrylamide) (PNIPAM) and poly(methoxy diethylene glycol acrylate) (PMDEGA), respectively, was comparatively investigated in a wide temperature range. Concentrated aqueous solutions containing 25 wt % polymer were studied by small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and broadband dielectric spectroscopy (BDS). DSC measurements show that, during the demixing phase transition, the hydration number per oligo(ethylene glycol) side chain in the PS- b-PMDEGA solution decreases rather gradually, even up to 20 °C above the onset of the transition, i.e., the cloud point (CP). In contrast, the PS- b-PNIPAM solution exhibits an abrupt, stepwise dehydration behavior at its CP, indicated by the sharp, narrow endothermic peak. BDS measurements suggest that the organization of the expelled water during the phase transition and the subsequent evolution of the micellar aggregates are different for the two copolymers. In the PS- b-PMDEGA solution, the long-range charge transport process changes significantly at its CP and strong interfacial polarization processes appear, probably due to charge accumulation at the interfaces between the micellar aggregates and the aqueous medium. On the contrary, in the PS- b-PNIPAM solution, the phase transition has only a marginal effect on the long-range conduction process and is accompanied by a reduction in the high-frequency (1 MHz) dielectric permittivity, ε'. The latter effect is attributed to the reduced polarization strength of local chain modes due to an enhancement of intra- and interchain hydrogen bonds (HBs) in the polymer-rich phase during the water detaching process. Surprisingly, our BDS measurements indicate that prior to both the demixing and remixing processes the local chain mobility increases temporally. Our dielectric studies suggest that for PS- b-PNIPAM the water detaching process initiates a few degrees below CP and that the local chain mobility and intra- and/or interchain HBs of the PNIPAM blocks may control its thermoresponsive behavior. Dielectric "jump" experiments show that the kinetics of micellar aggregation in the PS- b-PMDEGA solution is slower than that in the PS- b-PNIPAM solution and is independent of the target temperature within the two-phase region. From the experimental point of view, it is shown that the dielectric susceptibility, especially, the dielectric permittivity, ε', is a well-suited probe for monitoring both the reversible changes in the molecular dipolar bond polarizability and the long-range interfacial polarization at the phase transition.

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Section: Resultscontrasting

confidence: 60%

Section: Resultsmentioning

confidence: 96%

Comparative Investigation of the Thermoresponsive Behavior of Two Diblock Copolymers Comprising PNIPAM and PMDEGA Blocks

et al. 2018

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Kinetics of Collapse Transition and Cluster Formation in a Thermoresponsive Micellar Solution of P(S‐b‐NIPAM‐b‐S) Induced by a Temperature Jump

Adelsberger

Metwalli

Diethert

et al. 2012

Macromol. Rapid Commun.

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Structural changes at the intra- as well as intermicellar level were induced by the LCST-type collapse transition of poly(N-isopropyl acrylamide) in ABA triblock copolymer micelles in water. The distinct process kinetics was followed in situ and in real-time using time-resolved small-angle neutron scattering (SANS), while a micellar solution of a triblock copolymer, consisting of two short deuterated polystyrene endblocks and a long thermoresponsive poly(N-isopropyl acrylamide) middle block, was heated rapidly above its cloud point. A very fast collapse together with a multistep aggregation behavior is observed. The findings of the transition occurring at several size and time levels may have implications for the design and application of such thermoresponsive self-assembled systems.

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The micellization and dissociation transitions of thermo-, pH- and sugar-sensitive block copolymer investigated by laser light scattering

Tang¹,

Wu²,

Duan³

2012

Express Polym. Lett.

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Abstract.A triple-stimuli responsive polymer, poly(3-acrylamidophenylboronic acid)-b-poly(N-isopropylacrylamide) (PAAPBA-b-PNIPAM), has been synthesized by reversible addition-fragmentation chain transfer polymerization. Temperature, pH, and fructose induced micellization and dissociation transition of block copolymer was investigated by a combination of static and dynamic laser light scattering. PAAPBA-b-PNIPAM copolymer self-assembles into micelles with PAAPBA block as core and PNIPAM as shell in lower pH aqueous solution at room temperature. Increasing the temperature causes the micelle to shrink due to the dehydration of PNIPAM segments at pH 6.2. After the elevation of solution pH from 6.2 to 10.0, the increase in the hydrophilicity of PAAPBA block leads to an expulsion of unimers from micelles. In addition, the fructose addition further enhances the dissociation of micelles. Our experiments demonstrate that the micelle to unimer transition process proceeds via the step-by-step sequential expulsion of individual chains.

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Erratum: The collapse transition of poly(styrene-b-(N-isopropyl acrylamide)) diblock copolymers in aqueous solution and in thin films

Abstract: Due to a processing error the presentation of Fig. 7 was incorrect. The correct figure is given below.

Cited by 3 publications

References 43 publications

Comparative Investigation of the Thermoresponsive Behavior of Two Diblock Copolymers Comprising PNIPAM and PMDEGA Blocks

Comparative Investigation of the Thermoresponsive Behavior of Two Diblock Copolymers Comprising PNIPAM and PMDEGA Blocks

Kinetics of Collapse Transition and Cluster Formation in a Thermoresponsive Micellar Solution of P(S‐b‐NIPAM‐b‐S) Induced by a Temperature Jump

The micellization and dissociation transitions of thermo-, pH- and sugar-sensitive block copolymer investigated by laser light scattering

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