Rheological Test for the Homogeneity of Aqueous Blends of Associative Polymer Network and Entangled Linear Polymer

Chiba, Takamitsu; Katashima, Takuya; Urakawa, Osamu; Inoue, Tadashi

doi:10.1678/rheology.48.49

Cited by 5 publications

(5 citation statements)

References 23 publications

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“…In this review, we introduce the recent progress on this field using two model transient networks: hydrophobically ethoxylated modified urethane (HEUR) and Tetra-PEG slime. The former is one of the associative polymers, which has been utilized by many researchers [24][25][26][27][28][29]. The latter is a class of transient networks with regular network structures developed by our group, comprising of the multi-armed prepolymers [30].…”

Section: Introductionmentioning

confidence: 99%

Probing the Molecular Mechanism of Viscoelastic Relaxation in Transient Networks

Michida,

Chung,

Katashima

2023

Gels

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Hydrogels, which have polymer networks through supramolecular and reversible interactions, exhibit various mechanical responsibilities to its surroundings. The influence of the reversible bonds on a hydrogel’s macroscopic properties, such as viscoelasticity and dynamics, is not fully understood, preventing further innovative material development. To understand the relationships between the mechanical properties and molecular structures, it is required to clarify the molecular understanding of the networks solely crosslinked by reversible interactions, termed “transient networks”. This review introduces our recent progress on the studies on the molecular mechanism of viscoelasticity in transient networks using multiple methods and model materials. Based on the combination of the viscoelasticity and diffusion measurements, the viscoelastic relaxation of transient networks does not undergo the diffusion of polymers, which is not explained by the framework of conventional molecular models for the viscoelasticity of polymers. Then, we show the results of the comparison between the viscoelastic relaxation and binding dynamics of reversible bonds. Viscoelastic relaxation is primarily affected by “dissociation dynamics of the bonds” and “network structures”. These results are explained in the framework that the backbone, which is composed of essential chains supporting the stress, is broken by multiple dissociation events. This understanding of molecular dynamics in viscoelasticity will provide the foundation for designing transient networks.

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Section: Introductionmentioning

confidence: 99%

Probing the Molecular Mechanism of Viscoelastic Relaxation in Transient Networks

Michida,

Chung,

Katashima

2023

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“…Following their work, various models have considered the interplay between polymer-and crosslink dynamics as stickers, including the sticky Rouse model 20,21) , sticky reptation model [21][22][23][24] , and reversible gelation model 25,26) . Alternatively, considerable experimental studies have been conducted to elucidate the viscoelasticity of the transient networks by using thermoresponsive ABA block copolymers [27][28][29][30] , hydrophobically end-capped polymers [31][32][33][34][35][36][37] , ionomers 25,[31][32][33][34][35][36][37][38][39][40] , "slime" [41][42][43] , etc. In addition, some studies reported the use of wormlike (threadlike) micelles, which are also strongly relevant [44][45][46][47][48] .…”

Section: Introductionmentioning

confidence: 99%

Molecular Understanding of Viscoelasticity in Transient Polymer Networks Based on Multiple Methods

Katashima

2022

J. Soc. Rheol., Jpn

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Transient polymer networks are formed by dynamic crosslinks with a finite lifetime and therefore exhibit significant viscoelasticity, including non-Newtonian behaviors. Using the combination of multiple experimental techniques, such as viscoelastic measurements and spectroscopic analyses, these properties can be understood at the molecular level. This review classified transient polymer networks as side-chain and end-chain crosslinks, and viscoelastic studies of each type were presented. A combination of linear viscoelastic and spectroscopic methods revealed deviations between the viscoelastic properties of transient polymer networks and the molecular model. These deviations are sometimes attributed to dynamic heterogeneities potentially contained in the transient polymer network. These unexpected heterogeneous structures are challenging to control and impact viscoelasticity. Controlling and discussing these heterogeneities based on multiple experimental approaches is essential for a better molecular understanding of transient networks in the future.

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“…Because the reversible bond nature differs from the covalent bond, these crosslinks continuously bind and dissociate, where the translational diffusion of the constitutive polymers is permitted. As a result, the transient networks are not solid, but are liquid showing temporal elasticity (viscoelastic liquid) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Because they can slowly dissolve into a solvent and release the entrapped molecules, there have been many applications for drug-delivery carriers [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Decoupling between Translational Diffusion and Viscoelasticity in Transient Networks with Controlled Network Connectivity

Katashima

Kobayashi

Ishikawa

et al. 2022

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The mobility of sustained molecules is influenced by viscoelasticity, which is strongly correlated with the diffusional property in polymeric liquid. However, the study of transient networks formed by a reversible crosslink, which is the viscoelastic liquid, was insufficient due to the absence of a model system. We compare the viscoelastic and diffusional properties of the transient networks, using the model system with controlled network connectivity (Tetra-PEG slime). According to independent measurements of viscoelasticity and diffusion, the root-mean-square distance the polymer diffuses during the viscoelastic relaxation time shows a large deviation from the self-size of the polymer, which is contrary to the conventional understanding. This decoupling between viscoelasticity and diffusion is unique for transient networks, suggesting that the viscoelastic relaxation is not induced by the diffusion of one prepolymer, particularly in the network with low connectivity. These findings will provide a definite basis for discussion to understand the viscoelasticity in transient networks.

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Rheological Test for the Homogeneity of Aqueous Blends of Associative Polymer Network and Entangled Linear Polymer

Cited by 5 publications

References 23 publications

Probing the Molecular Mechanism of Viscoelastic Relaxation in Transient Networks

Probing the Molecular Mechanism of Viscoelastic Relaxation in Transient Networks

Molecular Understanding of Viscoelasticity in Transient Polymer Networks Based on Multiple Methods

Decoupling between Translational Diffusion and Viscoelasticity in Transient Networks with Controlled Network Connectivity

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