Self-Assembled Polyvinyl Alcohol–Tannic Acid Hydrogels with Diverse Microstructures and Good Mechanical Properties

Abstract

Fabrication of hydrogels with unique microstructures and better mechanical properties through the self-assembly of commercially available synthetic polymers and small molecules is of great scientific and practical importance. A type of physical hydrogels is prepared by the self-assembly of polyvinyl alcohol (PVA) and tannic acid (TA) in aqueous solution with a low PVA–TA concentration (0.5–6.0 wt %) at room temperature. With the increase of the PVA–TA concentration, the water content of the hydrogels increases, and the content of TA in the hydrogels decreases from 23.1 to 6.4%. The driving force for the self-assembly is proven to be the hydrogen bonding between PVA and TA, which also induces the crystallization of PVA chains. The self-assembled PVA–TA hydrogels have diverse morphologies that change from microspheres to oriented porous structures with the increase of the PVA–TA concentration, and these structures are all composed of nanosized particles, fibers, and/or sheets. Most of the self-assembled PVA–TA hydrogels show good mechanical properties. The highest tensile strength and elastic modulus of the PVA–TA hydrogel prepared with 1.0 wt % PVA–TA concentration are about 84 and 30 kPa, respectively. This self-assembly method would lead to the fabrication of more hydrogels with unique microstructures and properties for practical applications.

A Hydrogen‐Bonded Extracellular Matrix‐Mimicking Bactericidal Hydrogel with Radical Scavenging and Hemostatic Function for pH‐Responsive Wound Healing Acceleration

“…Instead, physical entanglement by naturally occurring polymers or materials can be a better option since they are usually cost-effective and biologically friendly, while the fabrication process is rapid, simple, and scalable. [23,24] For example, tannic acid (TA), a plant-derived polyphenol, has been recently attracted high attention for one-pot physical synthesis of hydrogels by numerous hydrogen bonding with other polymers, such as polyvinyl alcohol (PVA), [25] polyvinylpyrrolidone (PVP), [26] carboxylated agarose, [27] and DNA. [28] TA can render intrinsic anti-inflammatory, antioxidant, and antibacterial properties to the hydrogels.…”

High‐Performance PVA/PEDOT:PSS Hydrogel Electrode for All‐Gel‐State Flexible Supercapacitors

“…[33] PVA shows three typical peaks at 2θ = 19.8°, 22.9°, and 40.9°, corresponding to the (101), (200), and (102) planes of PVA semicrystal. [34] By comparison, EG-PPPH and PPPH show the same diffraction peaks as pristine PVA, indicating that the mixing of PEDOT:PSS and the treatment of EG did not affect the aggregation structure and crystalline state of the composite electrode material, thereby not reducing the final mechanical performance.…”

Preparation and characterization of a novel polysialic acid/gelatin composite hydrogels cross-linked by Tannic acid to improve healing and nursing care of cesarean section dressing

“…1. The pores contained in PSA-Gel-TA were much larger than commonly seen in hydrogels containing PSA-Gel, so the high porous structures were predominantly supported by TA molecules [25]. The wall thickness and pore size of PSA-Gel-TA hydrogels have also improved with the growth of TA.…”