Rheo-Optical and Dielectric Study on Dynamics of Bottlebrush-like Polymacromonomer Consisting of a Polyisoprene Main Chain and Polystyrene Side Chains

Iwawaki, Hiroshi; Urakawa, Osamu; Inoue, Tadashi; Nakamura, Yo; Watanabe, Hiroshi

doi:10.1021/acs.macromol.0c01041

Cited by 8 publications

(13 citation statements)

References 51 publications

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“…It should also be noted that the Zimm-like regime extends over decades within the frequency range. This behaviour is a typical response already reported in 3D macromolecules as highly branched dendrimers [ 13 , 14 , 15 , 16 ], bottlebrushes [ 17 , 18 , 19 , 20 ], highly functionalized stars [ 21 , 22 , 23 , 24 ].…”

Section: Resultssupporting

confidence: 73%

“…Besides the soft nanoparticles and microgels, a variety of macromolecular architectures, characterized by the lack of entanglements in the melt, has shown a similar rheological behaviour in the linear region. Examples are dendrimers [ 14 , 15 , 16 , 17 ], bottlebrushes [ 18 , 19 , 20 , 21 ], high functionalized stars [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] and dendronized polymers [ 26 , 27 , 28 ]. All these materials share certain rheological features as Rouse or Zimm-like dynamics, low values of the viscosity and high elastic character.…”

Section: Introductionmentioning

confidence: 99%

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Rheology of Poly(glycidyl methacrylate) Macromolecular Nano Assemblies

et al. 2022

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A recently reported combined polymerization process of glycidyl methacrylate, mediated by homometallic and heterobimetallic aluminium complexes, naturally produces nano-sized macromolecular assemblies. In this work, the morphological features and the rheological properties of these novel nanoassemblies are studied. The hydrodynamic sizes of the nanoparticles in the solution range from 10 to 40 nm (in numbers), but on a flat surface they adopt a characteristic thin disk shape. The dynamic moduli have been determined in a broad range of temperatures, and the time—temperature superposition applied to obtain master curves of the whole viscoelastic response from the glassy to the terminal regions. The fragility values obtained from the temperature dependence are of m ~40, typical of van de Waals liquids, suggesting a very effective packing of the macromolecular assemblies. The rheological master curves feature a characteristic viscoelastic relaxation with the absence of elastic intermediate plateau, indicating that the systems behaved as un-entangled polymers. The analysis of the linear viscoelastic fingerprint reveals a Zimm-like dynamics at intermediate frequencies typical of unentangled systems. This behaviour resembles that observed in highly functionalized stars, dendrimers, soft colloids and microgels.

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Section: Resultssupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Rheology of Poly(glycidyl methacrylate) Macromolecular Nano Assemblies

et al. 2022

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“…66,67 This phenomenon has been also observed in the bottlebrush polymer with short unentangled branches. 31,68 However, as opposed to the bottlebrush polymers, the pendent MNPs in Ps-B are solid and compact nanoparticles.…”

Section: T H I S C O N T E N T Imentioning

confidence: 99%

Hierarchical Dynamics of Nonsticky Molecular Nanoparticle-Tethered Polymers: End and Topology Effects

2022

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Segmental and chain dynamics of the type-A polyethers tethered with nonsticky polyhedral oligomeric silsesquioxane molecular nanoparticles (MNPs) have been investigated experimentally by a combination of broadband dielectric spectroscopy, rheology, and pulsed-field-gradient (PFG) nuclear magnetic resonance (NMR) techniques, to provide a fundamental understanding of the effects of chain ends and topology on the hierarchical dynamics of polymers. Series of poly(1,2-butylene oxide)s of a narrow molecular weight distribution with the MNPs tethered at one or two chain ends (denoted as P-B and P-B-P) or tethered at the side (denoted as P-s-B) have been elaborately designed and synthesized. Both dielectric segmental and chain relaxations of P-B and P-B-P were found to be retarded by the attachment of the MNPs at the ends. In contrast to traditional polymer glass transition behaviors, their dielectric glass transition temperatures (T g ) decrease with an increase in the molecular weight until saturated at the high-molecular weight limit, which has been ascribed to the relatively low mobility of the MNPs in comparison to those of the usual polymer end segments. The Flory−Fox equation has been modified to depict the tendency of T g versus molecular weight for P-B and P-B-P, which yields the equivalent number of segments for chain extension to account for the end effects of the MNPs on the segmental level. On the chain length scale, we found that the dielectric and rheological behaviors of the unentangled P-B and P-B-P complied with the predictions of the Rouse model in terms of the scaling law of the longest relaxation time versus the effective molecular weight and the relaxation spectra resolved in the low-p mode region, whereas a crossover from the Rouse to the reptation behavior was also observed. 29 Si PFG NMR spectroscopy has been utilized to selectively probe the diffusion of the MNPs attached to the polymers. The unique role of the MNP and its influence on the dynamics of polymers were further discussed in the context of hierarchically branched polymers. In contrast, the rheological behaviors of P-s-B with side-tethered MNPs revealed gradual disentangling of the chains with an increase in the number of MNPs and accelerated chain relaxation in comparison with that of P-B-P, reflecting the distinct topology effects of the MNPs on the polymer dynamics.

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“…Electronic devices for energy storage require high permittivity ( k ) materials. − Most importantly, high- k ceramic or conductive fillers are widely used as reinforcing phases in composite or hybrid materials. Such materials can be incorporated into flexible polymers with advantages of good mechanical and dielectric performance because of their potential applications in the field of flexible electronic devices including high-energy storage devices, organic field-effect transistors (OFETs), smart skins, and electrical power systems. − A variety of polymeric materials, such as poly(methyl methacrylate) (PMMA), , polystyrene (PS), polyacrylonitrile (PAN), polyimide (PI), poly(vinyl alcohol) (PVA), and poly(4-vinylphenol) (PVP), used as host materials have found application as dielectrics in OFETs and circuits. Among these materials, PI is considered to be one of the most important high-performance materials because of its excellent thermal stability and superior mechanical properties coupled with good chemical resistance. − Therefore, PI is desirable for applications in electrical fields as a durable polymer matrix …”

Section: Introductionmentioning

confidence: 99%

Thermally Robust Zirconia Nanorod/Polyimide Hybrid Films as a Highly Flexible Dielectric Material

Yan

Moon

Zhang

et al. 2021

ACS Appl. Nano Mater.

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In this study, a strategy for the fabrication of zirconia-polyimide (ZrO 2 -PI) nanohybrid films with high permittivity (high-k), thermal stability, and excellent mechanical properties has been developed. A colloidal suspension of ZrO 2 nanorods was prepared using the facile microwave-hydrothermal treatment approach. The ZrO 2 -PI nanohybrid film was fabricated by casting an aqueous solution containing water-soluble poly(amic acid) ammonium salt (PAS) and water-dispersible ZrO 2 nanorods followed by thermal imidization. Atomic force microscopy and scanning electron microscopy images indicated that the ZrO 2 nanorods were uniformly dispersed in the PI matrix. Because of the high permittivity of the ZrO 2 nanorods and good compatibility between polyimide and ZrO 2 as well as the nanosize of ZrO 2 , the permittivity increased to 5.1 as the ZrO 2 concentration reached 10% at 10 Hz, while the dielectric loss was as low as 0.05 at 10 Hz. The prepared ZrO 2 -PI nanohybrid films had excellent heat resistance with quite low coefficients of thermal expansion (CTE), as low as 16.3 ppm/K. The ZrO 2 -PI nanohybrid films have excellent thermal stability and good mechanical flexibility. Moreover, no distinct changes were observed for the PAS solution over a storage time of 3 months, after which the nanohybrid film could still be successfully synthesized by thermal imidization. In addition, the water uptake of the ZrO 2 -PI nanohybrid film was approximately 2.5% under 60% relative humidity. The high stability of the PAS precursor, good flexibility, enhanced permittivity, and low CTE behavior of the ZrO 2 -PI nanohybrid films could make this strategy attractive for the ecofriendly design of dielectric polymer nanohybrids as well as for the fabrication of nanohybrid films with potential applications in high charge-storage capacitors and organic field-effect transistors (OFETs) in the flexible electronics industry.

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Rheo-Optical and Dielectric Study on Dynamics of Bottlebrush-like Polymacromonomer Consisting of a Polyisoprene Main Chain and Polystyrene Side Chains

Cited by 8 publications

References 51 publications

Rheology of Poly(glycidyl methacrylate) Macromolecular Nano Assemblies

Rheology of Poly(glycidyl methacrylate) Macromolecular Nano Assemblies

Hierarchical Dynamics of Nonsticky Molecular Nanoparticle-Tethered Polymers: End and Topology Effects

Thermally Robust Zirconia Nanorod/Polyimide Hybrid Films as a Highly Flexible Dielectric Material

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