Determination of the local conformation of PMMA from wide-angle X-ray scattering

Lovell, R.; Windle, Alan H.

doi:10.1016/0032-3861(81)90195-6

Cited by 107 publications

(77 citation statements)

References 23 publications

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“…This is not only true for the coherent structure factor obtained from a fully deuterated material, but also for the five differently weighted partial structural factors which may be observed experimentally in labeling with deuterium at different positions of the molecule. The comparison with X-rays results reported in the literature [35][36][37] is successful as well. 21 Thus, the simulations lead to an overall good agreement with the experimental partial static structure factors.…”

Section: Validation Of Simulationsmentioning

confidence: 79%

Self- and Collective Dynamics of Syndiotactic Poly(methyl methacrylate). A Combined Study by Quasielastic Neutron Scattering and Atomistic Molecular Dynamics Simulations

et al. 2006

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We have investigated the molecular dynamics of syndiotactic poly(methyl methacrylate) well above the glass transition by combining quasielastic neutron scattering and fully atomistic computer simulations. The incoherent scattering measured by backscattering on a sample with deuterated ester methyl groups has revealed the single-particle motions of hydrogens in the main chain and in the R-methyl groups. Moreover, with neutron spin-echo experiments on the fully deuterated sample we have accessed the collective motions at the two first maxima of the structure factor. The simulated cell, which has been previously validated regarding the structural properties et al. Macromolecules 2006, 39, 3947], shows a dynamical behavior that, allowing a shift in temperature, reproduces very accurately all the experimental results. The combined analysis of both sets of data has shown that: (i) The segmental relaxation involving backbone atoms deviates from Gaussian behavior.(ii) The dynamics is extremely heterogeneous: in addition to the subdiffusion associated with the R-process and the methyl group rotations, we have found indications of a rotational motion of the ester side group around the main chain. (iii) At a given momentum transfer and depending on the molecular groups considered, the time scales for collective motion are spread over about 1 order of magnitude, the correlations involving the main chain decaying much more slowly than those relating side groups. (iv) At the length scale characteristic for the overall periodicity of the system (that corresponding to the first structure factor peak), the experimentally observed collective dynamics relates to the backbone motions and is of interchain character; there, coherency effects are observed for all correlations, though side groups display weaker collectivity. (v) At the second structure factor peak, coherency remains only for correlations involving the main chains.

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Section: Validation Of Simulationsmentioning

confidence: 79%

Self- and Collective Dynamics of Syndiotactic Poly(methyl methacrylate). A Combined Study by Quasielastic Neutron Scattering and Atomistic Molecular Dynamics Simulations

et al. 2006

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“…7) can be compared with the cylindrically-averaged scattering calculated from models. The scattering for a model chain segment, si(s, a), is cylindrically averaged about the axis of the segment by calculating [34]:…”

Section: Chain Conformationmentioning

confidence: 99%

Glassy poly(p-phenylene sulphide): determination of the local structure

Jones

Mitchell

Windle

1983

Colloid & Polymer Sci

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Methods are described for obtaining conformational and packing information about para-linked phenylene polymers from wide-angle X-ray scattering. On the basis of these procedures, together with conformational energy calculations, a random chain conformation is determined for non-crystalline poly(p-phenylene sulphide), in which the phenylene groups are rotated away from the coplanar position by 40 ~ and the conformation persists for -15/k. Whilst there is no evidence for parallel chain packing at any level, it is necessary to invoke local pairwise correlation of phenylene groups within an otherwise random chain packing system, to obtain satisfactory agreement with the experimental results.

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“…Wide-angle X-ray scattering analysis of an amorphous PMMA sample with similar tacticity has shown that, in spite of the amorphous state of the material, the conformation of the backbone is regular on a local scale of about 8 to 10 monomer units [38]. This conformation (Fig.…”

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confidence: 99%

Smectic E side-chain liquid crystalline poly(methacrylates)

et al. 1988

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Résumé. 2014 Une série homologue de trois poly(méthacrylates) liquides cristallins à groupes mésogènes latéraux a été étudiée par diffraction des rayons X. Les groupes mésogènes constitués par des groupes 4'-méthoxybiphénylyle étaient reliés au squelette macromoléculaire par des espaceurs souples de nature oligooxyéthyléniques. La structure smectique E monocouche de ces polymères a été analysée en termes de conformations du squelette macromoléculaire. Les groupes latéraux sont tous situés du même côté par rapport à la chaîne principale, et conduisent à des éléments de structure ayant la forme de rubans. Les rubans sont assemblés côte à côte avec les groupes mésogènes pointant alternativement vers le haut et vers le bas.Abstract. 2014 A homologous series of three side-chain liquid crystalline poly(methacrylates) with 4'-methoxybiphenylyl pendant mesogenic groups and oligo(ethylene-oxide) flexible spacers has been studied by X-ray diffraction. These polymers were shown to form a single layered smectic E structure, which has been analysed in terms of polymer chain conformation. The pendant groups were found to all hang on the same side of the polymer backbone to form ribbons, which are assembled side by side with an alternating up and down orientation of the pendant groups.

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Determination of the local conformation of PMMA from wide-angle X-ray scattering

Cited by 107 publications

References 23 publications

Self- and Collective Dynamics of Syndiotactic Poly(methyl methacrylate). A Combined Study by Quasielastic Neutron Scattering and Atomistic Molecular Dynamics Simulations

Self- and Collective Dynamics of Syndiotactic Poly(methyl methacrylate). A Combined Study by Quasielastic Neutron Scattering and Atomistic Molecular Dynamics Simulations

Glassy poly(p-phenylene sulphide): determination of the local structure

Smectic E side-chain liquid crystalline poly(methacrylates)

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