Macromol. Rapid Commun. 22/2010

Sakai, Takamasa; Akagi, Yuki; Matsunaga, Takuro; Kurakazu, Manami; Chung, Ung‐il; Shibayama, Mitsuhiro

doi:10.1002/marc.201090059

Cited by 31 publications

(40 citation statements)

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“…23 Here, a Tetra-PEG itself can be regarded as a cross linker, so we call this reaction "cross-link-coupling". [23][24][25][26][27][28][29][30][31][32] In reference 12 and 21, we demonstrated crossovers in the ߶ -dependence of the elastic modulus at approximately the overlapping concentration (߶ * ) and at the concentration where the elastic contribution of entangled chains become dominant. [23][24][25][26][27][28][29][30][31][32] In reference 12 and 21, we demonstrated crossovers in the ߶ -dependence of the elastic modulus at approximately the overlapping concentration (߶ * ) and at the concentration where the elastic contribution of entangled chains become dominant.…”

Section: Introductionmentioning

confidence: 96%

Supercoiling transformation of chemical gels

et al. 2015

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The swelling/deswelling behavior of chemical gels has been an unsolved problem disputed over for a long time. The Obukhov-Rubinstein-Colby model depicts the influence that swelling/deswelling has on elasticity, but its physical picture is too complicated to be sufficiently validated by experiment. In this study, we use molecular dynamics simulation to verify the validity of the molecular picture of network strands predicted by the Obukhov-Rubinstein-Colby model. We conclude that the physical picture of the Obukhov-Rubinstein-Colby model is reasonable, and furthermore the simulation can reveal the details of conformational changes in network strands during the supercoiling transformation. Our findings not only reveal the validity, but also give a better understanding of the dynamics of the swelling/deswelling behavior of chemical gels.

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Section: Introductionmentioning

confidence: 96%

Supercoiling transformation of chemical gels

et al. 2015

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“…21–27 A recent approach by Sakai and coworkers 28 utilized 4-arm star-shaped polymers to reduce network defects and form highly elastic, remarkably homogeneous hydrogels. 29 They achieved this through the use of tetra-arm PEG macromers that cross-link through activated-ester chemistry. The resulting gels, referred to as Tetra-PEG gels, were found to have a remarkably homogeneous network structure through small-angle neutron scattering (SANS) 30 and static-light scattering (SLS) studies.…”

Section: Introductionmentioning

confidence: 99%

SANS study of highly resilient poly(ethylene glycol) hydrogels

et al. 2014

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Polymer networks are critically important for numerous applications including soft biomaterials, adhesives, coatings, elastomers, and gel-based materials for energy storage. One long-standing challenge these materials present lies in understanding the role of network defects, such as dangling ends and loops, developed during cross-linking. These defects can negatively impact the physical, mechanical, and transport properties of the gel. Here we report chemically cross-linked poly(ethylene glycol) (PEG) gels formed through a unique cross-linking scheme designed to minimize defects in the network. The highly resilient mechanical properties of these systems (discussed in a previous publication1), suggests that this cross-linking technique yields more homogeneous network structures. Four series of gels were formed based on chains of 35,000 g/mol, (35K), 12,000 g/mol (12K) g/mol, 8,000 g/mol (8K) and 4,000 g/mol (4K) PEG. Gels were synthesized at five initial polymer concentrations ranging from 0.077 g/mL to 0.50 g/mL. Small-angle neutron scattering (SANS) was utilized to investigate the network structures of gels in both D2O and d-DMF. SANS results show the resulting network structure is dependent on PEG length, transitioning from a more homogeneous network structure at high molecular weight PEG to a two phase structure at the lowest molecular weight PEG. Further investigation of the transport properties inherent to these systems, such as diffusion, will aid to further confirm the network structures.

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“…The value of G′ is proportional to the concentration of elastically effective chains, whereas that of G″ is correlated with the topological defects[49]. Thus, more network defects exist when tanδ is large.…”

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confidence: 99%