Nanophase separation in side chain polymers: new evidence from structure and dynamics

Hiller, Sebastian; Pascui, Ovidiu; Budde, H.; Kabisch, O.; Reichert, Detlef; Beiner, Mario

doi:10.1088/1367-2630/6/1/010

Cited by 84 publications

(119 citation statements)

References 35 publications

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“…In particular, the hypothetic presence of two types of α relaxation is discussed in poly(n-alkyl-methacrylates) and poly(di-n-alkyl itaconates). [12][13][14] Two structural relaxations have also been reported for poly(isobornyl methacrylate), a polymer with a bulky bicyclic isobornyl side group. 15 In order to clarify the role played by side groups dynamics, it can be useful to reduce the complexity herited a) Electronic mail: a.arbe@ehu.es.…”

Section: Introductionmentioning

confidence: 94%

“…This peak is roughly in the same position as the "prepeak" in the x-ray pattern, reinforcing the idea that in polymers with bulky side groups such a "prepeak" is representative of the polymer backbone distance. 11,12,14,50,51 This average distance could be estimated from the peak position as 2π/0.6 Å −1 = 10.5 Å. S MC/MC (Q) smoothly decreases toward higher Q but still shows a small shoulder around 1.2 Å −1 , i.e., around the "main" peak.…”

Section: A Atomistic Approach 1 Short-range Order In Pvpmentioning

confidence: 99%

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Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

Busselez

Arbe

Álvarez

et al. 2011

The Journal of Chemical Physics

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Oxygen and nitrogen plasma hydrophilization and hydrophobic recovery of polymers Biomicrofluidics 6, 016501 (2012) Interferometric scanning microscopy for the study of disordered materials Appl. Phys. Lett. 99, 251912 (2011) (Electro)mechanical behavior of selectively solvated diblock/triblock copolymer blends Appl. Phys. Lett. 99, 242901 (2011) Statics of polymer droplets on deformable surfaces J. Chem. Phys. 135, 214703 (2011) Interactions between polymer brush-coated spherical nanoparticles: The good solvent case J. Chem. Phys. 135, 214902 (2011) Additional information on J. Chem. Phys. Quasielastic neutron scattering, x-ray diffraction measurements, and fully atomistic molecular dynamics simulations have been performed on poly(vinylpyrrolidone) homopolymer above its glass transition temperature. A "prepeak" appears in the x-ray diffraction pattern that shows the typical features of a first amorphous halo. From an effective description of the experimentally accessed incoherent scattering function of hydrogens in terms of a stretched exponential function, we observe enhanced stretching and a momentum-transfer dependence of the characteristic time different from that usually reported for more simple polymers (main-chain polymers or polymers with small side groups). The comparison with both kinds of experimental results has validated the simulations. The analysis of the simulated structure factor points to a nanosegregation of side groups (SG) and mainchains (MC). The detailed insight provided by the simulations on the atomic trajectories reveals a partial and spatially localized decoupling of MC and SG dynamics at length scales between the average SG-SG distance and the characteristic length of the backbone interchain correlations. Anomalous behavior in correlators calculated for the SG subsystem are found, like e.g., logarithmiclike decays of the density-density correlation function. They might be a consequence of the existing large dynamic asymmetry between SG and MC subsystems. Our results suggest that, as the SGs are spatially extended and chemically different from the backbone, they form transient nanosegregated domains. The dynamics of these domains show similar behavior to that found in other systems displaying large dynamic asymmetry.

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Section: Introductionmentioning

confidence: 94%

Section: A Atomistic Approach 1 Short-range Order In Pvpmentioning

confidence: 99%

Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

Busselez

Arbe

Álvarez

et al. 2011

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…[73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92] From X-ray diffraction experiments, where mostly carbons and oxygens are highlighted without the possibility of distinguishing mainchain and side-group contributions to the patterns, it was suggested that side groups of different monomeric units tend to aggregate forming self-assembled alkyl nanodomains [called PE-like nanodomains]. 84,88,93 The rich dynamical behavior was mainly investigated by calorimetric, dielectric, and mechanical techniques, that are not selective for the different processes at a molecular level.…”

Section: Polymers With Complex Monomeric Units Or/and Chain Architectmentioning

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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“…full symbols in Fig.1a) and (ii) the α PE process shows a strong-to-fragile transition (Fig.1b). It starts as an Arrhenius-like process in the butyl members with C=4 alkyl carbons per side chain and alkyl nanodomains having a typical dimension of about d≈0.5 nm and approaches a steepness index of m≈50 for dodecyl members with C=12 and d≈2 nm (Fig.1c) [2].…”

mentioning

confidence: 98%

Confined Dynamics in Nanophase-Separated Side Chain Polymers

Beiner¹

2006

AIP Conference Proceedings

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The relaxation behavior of different series of nanophase-separated side chain polymers with long alkyl groups is studied and compared with corresponding results from the literature. Characteristic for these homopolymers is that alkyl groups -belonging to different monomeric units and chains -aggregate to alkyl nanodomains with a typical dimension of about 0.5-2 nm. Relaxation spectroscopy data and calorimetric results show that a polyethylene-like glass transition (α PE ) occurs within these alkyl nanodomains. The α PE process appears at temperatures below the conventional glass transition (α) where the main chains soften. The features of the α PE process in higher poly(n-alkyl methacrylates), poly(n-alkyl acrylates), poly(di-alkyl itaconates), poly(α-n-alkyl β-L-asparates) or hairy rod polyimides are similar [1]. The influence of the alkyl nanodomain size on the α PE process is studied in detail. Common trends have been observed in all homologous series [1]. With increasing length of the alkyl groups and increasing size of the alkyl nanodomains (i) the glass temperature T g (α PE ) increases (cf. full symbols in Fig.1a) and (ii) the α PE process shows a strong-to-fragile transition (Fig.1b). It starts as an Arrhenius-like process in the butyl members with C=4 alkyl carbons per side chain and alkyl nanodomains having a typical dimension of about d≈0.5 nm and approaches a steepness index of m≈50 for dodecyl members with C=12 and d≈2 nm (Fig.1c) [2].These findings are interpreted in the picture of a hindered glass transition and are related to the discussion about dynamic heterogeneities in glass forming liquids. The process observed for the butyl members can be understood as a Johari-Goldstein process in alkyl nanodomains (β PE ). The question whether or not this process survives in larger alkyl nanodomains with a truly cooperative α PE process is discussed [3]. First experiments on quenched side chain polymers seem to indicate that similar localized motions exist also in higher members. The general importance of nanophase separation effects for an understanding of the dynamics of complex materials in nanotechnology and nature will be discussed. References

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Nanophase separation in side chain polymers: new evidence from structure and dynamics

Cited by 84 publications

References 35 publications

Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

Study of the structure and dynamics of poly(vinyl pyrrolidone) by molecular dynamics simulations validated by quasielastic neutron scattering and x-ray diffraction experiments

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

Confined Dynamics in Nanophase-Separated Side Chain Polymers

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