Rheological properties and the mechanical signatures of phase transitions in weakly-segregated rod-coil block copolymers

Olsen, Bradley D.; Teclemariam, Nerayo P; Müller, Susan; Segalman, Rachel A.

doi:10.1039/b817680a

Cited by 12 publications

(11 citation statements)

References 45 publications

(66 reference statements)

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“…Cole‐Cole plots or Han plots provide a technique for analyzing polymers that is independent of the empirical shift factor used in TTS 42 . G ′ versus G ″ plots from frequency sweep experiments are independent of the melting temperature for monodisperse polymers 43.…”

Section: Resultsmentioning

confidence: 99%

Structure and Rheological Behavior of Thermoreversible Supramolecular Polymers with Weak Multiple Hydrogen Bonds

Chen¹,

Wu²,

Himmel³

et al. 2012

Macro Materials & Eng

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Thermoreversible supramolecular polymers are prepared from polyamide oligomers as backbones with weak multiple hydrogen bonds. The supramolecular polymers behave like elastic polymers with a high rubber plateau and a low melting temperature, which is favorable for low temperature processing. The end‐capped sulfonyl isocyanate increases the diversity of the self‐complementary hydrogen bonds. The melt rheology of the supramolecular polymers is highly dependent on temperature and is related to the structure of the physical network. The supramolecular polymers are yield stress fluids with a high yield stress of about 2557 kPa. The temperature dependence of hydrogen‐bonding is analyzed. Tensile tests are performed and are discussed in relation to the network structure.

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Section: Resultsmentioning

confidence: 99%

Structure and Rheological Behavior of Thermoreversible Supramolecular Polymers with Weak Multiple Hydrogen Bonds

Chen¹,

Wu²,

Himmel³

et al. 2012

Macro Materials & Eng

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“…Soft materials exhibit a rich range of rheological behaviors that play a central role in determining their processing behavior and practical functions. Examples include the engineered materials for biomedical applications, 1 self-healing materials for synthetic skin and flexible electronics, 2 self-assembling copolymers for nanopatterning, 3 and the active cytoskeleton of living cells. 4 The rheology of soft materials is governed by physical processes that occur over a vast range of time scales, 5 which presents a formidable challenge for unlocking the molecular underpinnings of viscoelastic behavior.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Light Scattering Microrheology Reveals Multiscale Viscoelasticity of Polymer Gels and Precious Biological Materials

et al. 2017

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The development of experimental techniques capable of probing the viscoelasticity of soft materials over a broad range of time scales is essential to uncovering the physics that governs their behavior. In this work, we develop a microrheology technique that requires only 12 μL of sample and is capable of resolving dynamic behavior ranging in time scales from 10–6 to 10 s. Our approach, based on dynamic light scattering in the single-scattering limit, enables the study of polymer gels and other soft materials over a vastly larger hierarchy of time scales than macrorheology measurements. Our technique captures the viscoelastic modulus of polymer hydrogels with a broad range of stiffnesses from 10 to 104 Pa. We harness these capabilities to capture hierarchical molecular relaxations in DNA and to study the rheology of precious biological materials that are impractical for macrorheology measurements, including decellularized extracellular matrices and intestinal mucus. The use of a commercially available benchtop setup that is already available to a variety of soft matter researchers renders microrheology measurements accessible to a broader range of users than existing techniques, with the potential to reveal the physics that underlies complex polymer hydrogels and biological materials.

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“…2, 5–7 Although the equilibrium thermodynamics of rod-coil block copolymers continues to be widely investigated, few studies have measured dynamic phenomena in these systems. Rheological measurements have been used to identify order-disorder transitions 8–9 and to measure intrinsic viscosities. 10 Borsali, et al also provided analytical expressions for dynamic structure factors in dilute solution.…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurement of Coil–Rod–Coil Block Copolymer Tracer Diffusion through Entangled Coil Homopolymers

2013

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The diffusion of coil-rod-coil triblock copolymers in entangled coil homopolymers is experimentally measured and demonstrated to be significantly slower than rod or coil homopolymers of the same molecular weight. A model coil-rod-coil triblock was prepared by expressing rodlike alanine-rich α-helical polypeptides in E. coli and conjugating coillike poly(ethylene oxide) (PEO) to both ends to form coil-rod-coil triblock copolymers. Tracer diffusion through entangled PEO homopolymer melts was measured using forced Rayleigh scattering at various rod lengths, coil molecular weights, and coil homopolymer concentrations. For rod lengths, L, that are close to the entanglementh length, a, the ratio between triblock diffusivity and coil homopolymer diffusivity decreases monotonically and is only a function of L/a, in quantitative agreement with previous simulation results. For large rod lengths, diffusion follows an arm retraction scaling, which is also consistent with previous theoretical predictions. These experimental results support the key predictions of theory and simulation, suggesting that the mismatch in curvature between rod and coil entanglement tubes leads to the observed diffusional slowing.

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Rheological properties and the mechanical signatures of phase transitions in weakly-segregated rod-coil block copolymers

Cited by 12 publications

References 45 publications

Structure and Rheological Behavior of Thermoreversible Supramolecular Polymers with Weak Multiple Hydrogen Bonds

Structure and Rheological Behavior of Thermoreversible Supramolecular Polymers with Weak Multiple Hydrogen Bonds

Dynamic Light Scattering Microrheology Reveals Multiscale Viscoelasticity of Polymer Gels and Precious Biological Materials

Experimental Measurement of Coil–Rod–Coil Block Copolymer Tracer Diffusion through Entangled Coil Homopolymers

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