Mean-Square Electric Dipole Moment of Oligo- and Poly(methyl methacrylate)s in Dilute Solution

Ando, Hitoshi; Yoshizaki, Takenao; Aoki, A.; Yamakawa, Hiromi

doi:10.1021/ma970501d

Cited by 12 publications

(5 citation statements)

References 49 publications

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“…It has been shown that there is rather good agreement between theory and experiment with respect to the dependence on x of the mean-square optical anisotropy <F 2 ) for a-PS/ 5 · 36 a-PMMA, 36 and i-PMMA 37 in the respective e solvents, and also of the mean-square electric dipole moment <11 2 ) for a-and i-PMMAs in the respective e solvents 38 and poly( dimethylsiloxane) (PDMS) in cyclohexane at 25.0oC. 39 However, an explanation of <11 2 ) for a-and i-PMMAs requires a consideration of possible effects of chain ends since their moments arise from the side groups; this is in contrast to the case of PDMS having rigid perpendicular (type-B) dipoles.…”

Section: Some Other Topicsmentioning

confidence: 82%

A New Framework of Polymer Solution Science. The Helical Wormlike Chain

Yamakawa

1999

Polym J

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ABSTRACT:The object of this review article is to introduce and digest Yamakawa's new book, "Helical Wormlike Chains in Polymer Solutions." A brief description is given of a new model for polymer chains, called the helical wormlike chain, and its applications to dilute solution behavior of polymers, that is, equilibrium, steady-state transport, and dynamical properties. The description follows most of the chapters of the book. It is shown that all theoretical and experimental investigations on the basis of this model provide a new framework of polymer solution science, which takes the place of the Flory-Kirkwood framework.KEY The object of this review article is to introduce and digest Yamakawa's new book 1 entitled" Helical Wormlike Chains in Polymer Solutions." As stated in its Preface, it is intended to give a comprehensive and systematic description of the statistical-mechanical, transport, and dynamic theories of dilute solution properties of both flexible and semiflexible polymers, including oligomers, developed on the basis of the "helical wormlike (HW) chain" model, along with an analysis of extensive experimental data. Much of the material in the book arises from his research reported since the year of publication of his earlier (1971) book. 2 The results of this research were already very often reviewed. 3 -7 Now the framework of polymer solution theory constructed by Flory 8 • 9 consists of three concepts: (I) the excluded-volume effect in long flexible (Gaussian) polymer chains, (2) the universality of the unperturbed ( EJ) state without that effect, and (3) the rotational isomeric state (RIS) model for (unperturbed) real chains of arbitrary length. The study of dilute solution behavior of flexible polymers based on the first two concepts was almost completed around 1970, leading to the so-called two-parameter (TP) theory. 2 It is at almost the same time that the statistical-mechanical method for treating the RIS model, which takes account of the details of the chemical structure and local conformations of the chain on the atomic level, was established by Flory and coworkers.9 However, for many equilibrium and steadystate transport problems on stiff or semiflexible polymers, such details are not amenable to mathematical treatments, and moreover are often unnecessary to consider. Some coarse-graining may then be introduced to replace this discrete model by continuous models. In 1976, for this purpose we proposed a general continuous model, called the HW chain. 10 This new model may describe equilibrium conformational and steady-state transport properties of all kinds of real chains, both flexible and stiff, on the bond length or somewhat longer scales, thus bridging a gap between the RIS model and the classical continuous model, that is, the KratkyPorod (KP) wormlike chain. 11 Specifically, the transport t Professor Emeritus.

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Section: Some Other Topicsmentioning

confidence: 82%

A New Framework of Polymer Solution Science. The Helical Wormlike Chain

Yamakawa

1999

Polym J

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“…Different stereocomplexes of PMMA, isotactic ( i -PMMA), atactic ( a -PMMA), and syndiotactic ( s -PMMA) that are used here differ only in chirality, yet i -PMMA has a larger mean-square dipole moment ‹ μ 2 › due to a larger degree of chain order. Measured bulk values of ‹ μ 2 › are also heavily dependent upon chain length; monomers (o1-PMMA) or oligomers (trimeric o3-PMMA) of PMMA have larger ‹ μ 2 › and thus are expected to undergo larger Stark shift in the same local solvent environment as compared with longer chains 28 . Morphologically induced ordering also affects dielectric properties, and PMMA nanodomains in PS-PMMA copolymers have been observed to have unusually large dielectric permittivity as evidenced by large Stark shifts of a dye molecule probe 29 .…”

Section: Resultsmentioning

confidence: 99%

Vibrational nano-spectroscopic imaging correlating structure with intermolecular coupling and dynamics

et al. 2014

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Molecular self-assembly, the function of biomembranes and the performance of organic solar cells rely on nanoscale molecular interactions. Understanding and control of such materials have been impeded by difficulties in imaging their properties with the desired nanometre spatial resolution, attomolar sensitivity and intermolecular spectroscopic specificity. Here we implement vibrational scattering-scanning near-field optical microscopy with high spectral precision to investigate the structure–function relationship in nano-phase separated block copolymers. A vibrational resonance is used as a sensitive reporter of the local chemical environment and we image, with few nanometre spatial resolution and 0.2 cm−1 spectral precision, solvatochromic Stark shifts and line broadening correlated with molecular-scale morphologies. We discriminate local variations in electric fields between nano-domains with quantitative agreement with dielectric continuum models. This ability to directly resolve nanoscale morphology and associated intermolecular interactions can form a basis for the systematic control of functionality in multicomponent soft matter systems.

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“…Under the influence of electrical forces, the rotating molecules impulse, twitch, and collide with other molecules, distributing the energy to adjacent molecules and atoms in the material and that energy appears as heat. − We suggest that, although polystyrene is microwave transparent, the other blocks in the BCPs viz. , polymethylmethacrylate and polydimethylsiloxane, are polar , and these polar molecules interact with the oscillating field resulting in dipole rotation and this rotation drives microphase separation. This may be through direct heating or via chain movements excited by the irradiating radiation.…”

Section: Discussionmentioning

confidence: 99%

Swift Nanopattern Formation of PS-b-PMMA and PS-b-PDMS Block Copolymer Films Using a Microwave Assisted Technique

et al. 2013

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Microphase separation of block copolymer (BCPs) thin films has high potential as a surface patterning technique. However, the process times (during thermal or solvent anneal) can be inordinately long, and for it to be introduced into manufacturing, there is a need to reduce these times from hours to minutes. We report here BCP self-assembly on two different systems, polystyrene-b-polymethylmethacrylate (PS-b-PMMA) (lamellar- and cylinder-forming) and polystyrene-b-polydimethylsiloxane (PS-b-PDMS) (cylinder-forming) by microwave irradiation to achieve ordering in short times. Unlike previous reports of microwave assisted microphase segregation, the microwave annealing method reported here was undertaken without addition of solvents. Factors such as the anneal time and temperature, BCP film thickness, substrate surface type, etc. were investigated for their effect of the ordering behavior. The microwave technique was found to be compatible with graphoepitaxy, and in the case of the PS-b-PDMS system, long-range translational alignment of the BCP domains was observed within the topographic patterns. To demonstrate the usefulness of the method, the BCP nanopatterns were turned into an 'on-chip' resist by an initial plasma etch and these were used to transfer the pattern into the substrate.

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Mean-Square Electric Dipole Moment of Oligo- and Poly(methyl methacrylate)s in Dilute Solution

Cited by 12 publications

References 49 publications

A New Framework of Polymer Solution Science. The Helical Wormlike Chain

A New Framework of Polymer Solution Science. The Helical Wormlike Chain

Vibrational nano-spectroscopic imaging correlating structure with intermolecular coupling and dynamics

Swift Nanopattern Formation of PS-b-PMMA and PS-b-PDMS Block Copolymer Films Using a Microwave Assisted Technique

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