The collapse transition and the segmental dynamics in concentrated micellar solutions of P(S-b-NIPAM) diblock copolymers

Adelsberger, Joseph; Meier-Koll, Andreas; Bivigou-Koumba, Achille M.; Busch, Peter; Holderer, Olaf; Hellweg, Thomas; Laschewsky, André; Müller‐Buschbaum, Peter; Papadakis, Christine M.

doi:10.1007/s00396-011-2382-3

Cited by 33 publications

(59 citation statements)

References 43 publications

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“…Starting at -values larger than 0.14 Å −1 the scattering functions decay to zero. This is similar to our previous experiments [28,49], but differs from a study by Koizumi et al [53] for macrogels and from a recent work by Richtering et al for microgels [31].…”

Section: Nse Experimentssupporting

confidence: 65%

The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study

Hertle

Zeiser

Fouquet

et al. 2014

Zeitschrift Für Physikalische Chemie

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Microgels are generally synthesised above the lower critical solution temperature (LCST) of the used polymer (poly(N-isopropyl-acrylamide)(PNIPAM) in the present case) and there is evidence that, due to the "bad" solvent conditions and due to the differences in reactivity between the monomers and the crosslinker, an inhomogeneous crosslinker distribution in the network is created. In contrast, macrogels are statistically crosslinked, because they are polymerised below the LCST (good solvent conditions). With the neutron spin-echo (NSE) technique, the diffusion of the polymer network on a local length scale can be studied. Due to essentially different crosslinker distributions in the micro-and macrogels, a difference in the collective diffusion of the network could be expected. However, the measured intermediate scattering functions of the studied micro-and macrogel are similar and can both be described by a single exponential decay without a -dependent baseline. Hence, both systems behave pseudo-ergodically on the length scale available in the NSE experiment. A determination of the diffusion coefficient of the breathing mode of the gel network and the dynamic correlation length leads to comparable values for the homologous micro-and macrogels. The studied microgels contain butenoic acid as comonomer and also the pH dependence of the network dynamics is investigated.

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Section: Nse Experimentssupporting

confidence: 65%

The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study

Hertle

Zeiser

Fouquet

et al. 2014

Zeitschrift Für Physikalische Chemie

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“…This bridging is supported by the high value of ϕ compared with the one in diblock copolymers. [ 25 ] In the same time and temperature range, the volume fraction of correlated micelles ϕ decreases towards T c , thus the correlation is partially lost (Figure 3 b). As T c is crossed, r mic decreases from 16.7 nm to 6.5 nm within 0.8 s. The collapse of the shell thus takes less than 1 s.…”

Section: Methodsmentioning

confidence: 91%

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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“…NSE would be sensitive only to the very mobile segments, resulting in an average diffusion coefficient higher than in the swollen state. An analogous study of the same group on solutions of diblock copolymers PS-b-PNIPAM 60 revealed a more complex collapse transition that was associated to the absence of bridging. Again breathing modes were found for the PNIPAM shell, that become slower with increasing polymer concentration and (apparently) faster when heating above the collapse transition.…”

Section: Figure 12mentioning

confidence: 98%

“…53 Finally, hydrated polymers and polymer solutions-in particular, microgels-have also recently been investigated by QENS. [54][55][56][57][58][59][60][61][62][63] Studies on concentrated aqueous solutions show that confinement effects also arise -in this case for the minority water component-when the polymer freezes approaching its glass-transition. The component dynamics in these solutions can be selectively monitored by QENS, a task that is not easily achievable by other usually applied experimental approaches like, for example, dielectric spectroscopy.…”

Section: Recent Progress On Polymer Dynamics By Neutron Scatteringmentioning

confidence: 99%

Recent progress on polymer dynamics by neutron scattering: From simple polymers to complex materials

Colmenero

Arbe

2012

J Polym Sci B Polym Phys

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ABSTRACT:The recent (from 2010 onward) contributions of quasielastic neutron scattering techniques (time of flight, backscattering, and neutron spin echo) to the characterization and understanding of dynamical processes in soft materials based on polymers are analyzed. The selectivity provided by the combination of neutron scattering and isotopic-in particular, proton/deuterium-labeling allows the isolated study of chosen molecular groups and/or components in a system. This opportunity, together with the capability of neutrons to provide space/time resolution at the relevant length scales in soft matter, allows unraveling the nature of the large variety of molecular motions taking place in materials of increasing complexity. As a result, recent relevant works can be found dealing with dynamical process which associated characteristic lengths and nature are as diverse as, for example, phenyl motions in a glassy linear homopolymer like polystyrene and the chain dynamics of a polymer adsorbed on dispersed clay platelets. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 51: 2013 KEYWORDS: molecular dynamics; neutron scattering; relaxation POLYMER DYNAMICS AT DIFFERENT LENGTH AND TIME SCALES: FROM SIMPLE POLYMERS TO COMPLEX MATERIALSPolymers are composed of macromolecules which are built up by a large number N of monomer units linked together by covalent bonds. Because of this macromolecular nature, the structural and dynamic properties of polymeric systems strongly depend on a hierarchy of length and time scales. From a structural point of view, the random coil shape of linear polymer chains in the melt and glassy state-proposed by Flory in the 50s 1 -is nowadays well established by small angle neutron diffraction (SANS). At smaller length scales than those characteristic for the chain dimensions, the local arrangements of the atoms give rise to broad maxima in the static structure factor S(Q) also accessible by neutron diffraction. Usually, a first main peak centered at Q-values ≈ 1 . . . 1.5 Å −1 is present. The T-dependence of this maximum, following the expansion coefficient, indicates an interchain origin, that is, it mainly relates to correlations between atoms belonging to different chains (or to the same chain but well separated segments).2 A second peak located at ∼3 Å −1can also be usually found in S(Q). The small value of the associated characteristic length and its weak T-dependence indicate the intrachain nature of the correlations giving rise to this maximum. We also note that the broadening of the Bragg peaks found in polymers reveals a clear amorphous character. In fact, the features shown in S(Q) in polymeric systems are universal for amorphous materials, not only for polymers, and in particular for glass forming systems. Thus, a universal behavior common for all glass forming materials can also be expected in the dynamics, including the observation of the glass transition phenomenon. 3As anticipated, the complexity of amorphous polymers shows up not only in the structural propertie...

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The collapse transition and the segmental dynamics in concentrated micellar solutions of P(S-b-NIPAM) diblock copolymers

Cited by 33 publications

References 43 publications

The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study

The Internal Network Dynamics of Poly(NIPAM) Based Copolymer Micro- and Macrogels: A Comparative Neutron Spin-Echo Study

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

Recent progress on polymer dynamics by neutron scattering: From simple polymers to complex materials

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