Effect of stereoregularity and molecular weight on the mechanical properties of poly(vinyl alcohol) hydrogel

Fukae, Ryohei; Yoshimura, Michihiro; Yamamoto, Tohei; Nishinari, Katsuyoshi

doi:10.1002/app.33187

Cited by 15 publications

(8 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The longer molecular chains with more entangled points in starting solution can also benefit to construct denser network after freeze–thaw treatment reflected by the stronger mechanical properties of the formed gels with the similar trend of yields (Figure S2). The same trend of gel strength and yields with M w revealed that a high molecular size resulted in better association of molecular chains, implying that the formation of HA cryogels proceeded in a manner similar to that of physical PVA cryogels …”

Section: Results and Discussionmentioning

confidence: 65%

“…Such a cryotropic HA gel (cryogel) resulting from cryogelation that occurs upon cryogenic treatment of the initial solution was first reported by Okamoto and Miyoshi and is produced by one-time or repeated freeze–thaw cycles. It is known that as the polymeric concentration is increased by conversion of the solvent of water to ice resulting in the occurrence of a phase separation, the forced alignment of polymer chains in polymer-rich phases provides a mechanism for the formation of side-by-side associations that remain intact on thawing, acting as the junction zones of the hydrogel. , HA cryogel has since been used in a broad range of medical applications. ,, Apart from HA, many other natural polymers such as xanthan gum, β-glucan, locust bean gum, starch, carboxymethyl cellulose, and carboxymethylated Curdlan, ,− as well as some synthetic polymers, typically poly(vinyl alcohol) (PVA), can reportedly form cryogels by freezing and thawing their aqueous solutions. Initial factors affecting cryogel formation (such as the molecular size of the material) and those related to processing steps (such as freezing time, number of freeze–thaw cycles, freezing or thawing temperatures, etc.)…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Freeze–Thaw-Induced Gelation of Hyaluronan: Physical Cryostructuration Correlated with Intermolecular Associations and Molecular Conformation

et al. 2017

View full text Add to dashboard Cite

Physically cross-linked hydrogels from hyaluronan (hyaluronic acid, HA) were prepared by a freeze−thaw technique at low pH. The effect of the freezing−thawing of HA solutions on the formation of physical cryogels is typical for the processes of noncovalent cryostructuration that takes the advantages of mild fabrication conditions and the absence of organic solvents and toxically cross-linking agents. The effects of processing steps (freezing time and number of freeze−thaw cycles), HA molecular weight (M w ), and the addition of typical polycarboxylic and polyhydric small molecules such as dicarboxylic acids and polyols on the formation of HA cryotropic hydrogels were investigated. Results verified that long freezing time and repeated freeze−thaw cycles benefited the alignment of polymer chains in the unfrozen liquid microphase, thereby promoting the formation of intermolecular aggregations and dense fibrillar network structures. High M w of HA endowed the cryogel with strong mechanical strength. The influences of various small molecules on the cryogelation of HA revealed the different intermolecular association patterns in the gel network. Both succinic and glutaric acids participated in HA cryogelation, whereas oxalic, malic, and tartaric acids as well as some polyols (glycol, butanediol, and glycerol) inhibited the cryostructuration of HA. Hydrogen bonding and intermolecular interactions in acidic cryogels and in neutral cryogels obtained by in situ neutralizing the acidic cryogel were discussed at the molecular level in correlation with intermolecular associations and molecular conformation. A gelation mechanism for HA cryogel was proposed. In addition, experimental findings showed that the neutral HA cryogels possessed enhanced thermostability, resistance to acid decomposition, and enzyme degradation which are essentially important properties for biomaterials.

show abstract

Section: Results and Discussionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Freeze–Thaw-Induced Gelation of Hyaluronan: Physical Cryostructuration Correlated with Intermolecular Associations and Molecular Conformation

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Thus, in production of fibrils, the use of s‐PVA afforded a higher degree of polymer crystallinity13 and increased tensile strength;14 increased syndiotacticity of PVA afforded hydrogels with improved mechanical characteristics, e.g. dynamic storage,15, 16 compressive,17 and elastic moduli18 as well as markedly increased melting temperature 19, 20. In other words, with PVA, a sub‐molecular level of polymer engineering affords an astonishing enhancement in the degree of polymer association, i.e.…”

Section: (Sub)molecular Polymer Engineeringmentioning

confidence: 99%

Poly(Vinyl Alcohol) Physical Hydrogels: New Vista on a Long Serving Biomaterial

Alves

Jensen

Smith

et al. 2011

Macromolecular Bioscience

209

159

View full text Add to dashboard Cite

Poly(vinyl alcohol), PVA, and physical hydrogels derived thereof have an excellent safety profile and a successful history of biomedical applications. However, these materials are hardly in the focus of biomedical research, largely due to poor opportunities in nano- and micro-scale design associated with PVA hydrogels in their current form. In this review we aim to demonstrate that with PVA, a (sub)molecular control over polymer chemistry translates into fine-tuned supramolecular association of chains and this, in turn, defines macroscopic properties of the material. This nano- to micro- to macro- translation of control is unique for PVA and can now be accomplished using modern tools of macromolecular design. We believe that this strategy affords functionalized PVA physical hydrogels which meet the demands of modern nanobiotechnology and have a potential to become an indispensable tool in the design of biomaterials.

show abstract

“…A freezing‐and‐thawing method is widely used in the gelation process to induce the formation of physically crosslinked hydrogels such as hyaluronic acid and poly(vinyl alcohol) . These hydrogels can become strengthened by repeated freezing‐and‐thawing postprocessing for complete formation of weak interactions.…”

Section: Resultsmentioning

confidence: 99%

An injectable and self‐healing novel chitosan hydrogel with low adamantane substitution degree

Cheng

Yang

Qiao

et al. 2019

Polymer International

View full text Add to dashboard Cite

Chitosan (CS) is a semi-natural polymer with supreme biological function, while the strong interchain hydrogen bonds cause poor water solubility and limit its broader use. To break the semi-rigid structure of CS, a kind of CS modified by adamantane (AD-CS) was successfully synthesized by amidation reaction with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as catalyst. The chemical structure of AD-CS was characterized by Fourier transform infrared spectroscopy and 1 H NMR. The AD substitution degree of CS is around 2%, calculated by 1 H NMR. A soft and transparent hydrogel composed of hydrogen bonds was obtained directly by simply adding a certain amount of water under mild conditions. Rheological measurements were carried out to research the mechanism of hydrogel formation by measuring the influence of different additives and conditions on the AD-CS hydrogel. Reinforced hydrogels were prepared by freezing and thawing. The mechanical strength and self-healing property of reinforced and pristine hydrogels were assessed with an oscillatory rheometer. The modulus of the reinforced hydrogel was obviously enhanced without much loss of self-healing property. Other properties such as adhesion, injectability and temperature response were also studied. These injectable and self-healing hydrogels show potential value in medical care. Additionally, this is a new method to design CS hydrogels with their original interchain hydrogen bonds.

show abstract

Effect of stereoregularity and molecular weight on the mechanical properties of poly(vinyl alcohol) hydrogel

Cited by 15 publications

References 28 publications

Freeze–Thaw-Induced Gelation of Hyaluronan: Physical Cryostructuration Correlated with Intermolecular Associations and Molecular Conformation

Freeze–Thaw-Induced Gelation of Hyaluronan: Physical Cryostructuration Correlated with Intermolecular Associations and Molecular Conformation

Poly(Vinyl Alcohol) Physical Hydrogels: New Vista on a Long Serving Biomaterial

An injectable and self‐healing novel chitosan hydrogel with low adamantane substitution degree

Contact Info

Product

Resources

About