Electrospun Poly(vinyl alcohol)-Based Conductive Semi-interpenetrating Polymer Network Fibrous Hydrogel: A Toolbox for Optimal Cross-Linking

Abstract

Cross-linking of poly(vinyl alcohol) (PVA) creates a three-dimensional network by bonding adjacent polymer chains. The cross-linked structure, upon immersion in water, turns into a hydrogel, which exhibits unique absorption properties due to the presence of hydrophilic groups within the PVA polymer chains and, simultaneously, ceases to be soluble in water. The properties of PVA can be adjusted by chemical modification or blending with other substances, such as polymers, e.g., conductive poly[3-(potassium-5-butanoate)thiophene-2,5-diyl] (P3KBT). In this work, PVA-based conductive semi-interpenetrating polymer networks (semi-IPNs) are successfully fabricated. The systems are obtained as a result of electrospinning of PVA/P3KBT precursor solutions with different polymer concentrations and then cross-linking using “green”, environmentally safe methods. One approach consists of thermal treatment (H), while the second approach combines stabilization with ethanol and heating (E). The comprehensive characterization allows to evaluate the correlation between the cross-linking methods and properties of nanofibrous hydrogels. While both methods are successful, the cross-linking density is higher in the thermally cross-linked samples, resulting in lower conductivity and swelling ratio compared to the E-treated samples. Moreover, the H-cross-linked systems have better mechanical propertieslower stiffness and greater tensile strength. All the tested systems are biocompatible, and interestingly, due to the presence of P3KBT, they show photoresponsivity to solar radiation generated by the simulator. The results indicate that both methods of PVA cross-linking are highly effective and can be applied to a specific system depending on the target, e.g., biomedical or electronic applications.

Cross-linking electrospinning

“…For example, recently, Zakrzewska et al employed the cross-linking e-spinning of PVA/poly[3-(potassium-5-butanoate)thiophene-2,5-diyl] (P3KBT, a semiconductive polymer) to prepare a conductive fibrous hydrogel. 145 In this process, two cross-linking methods, namely, thermal treatment (160 °C, 2 h) and ethanol immersion (24 h) with heating (160 °C, 20 min), were used to fabricate semi-interpenetrating polymer networks, in which PVA was cross-linked, while non-cross-linked P3KBT was trapped in the PVA networks and remained the linear molecular form. The results indicated that thermal treatment was a more effective cross-linking method, resulting in composite materials with lower conductivity because the generated dense network structures could hinder charge transfer.…”

In Situ Engineering of Conducting Polymer Nanocomposites at Liquid/Liquid Interfaces: A Perspective on Fundamentals to Technological Significance

“…To date, numerous conducting polymers and their derivatives have gained significant acceptance, including polyacetylene, polypyrrole (PPy), polyaniline (PANI), poly­( p -phenylenevinylene), poly­(3,4-ethylenedioxythiophene) (PEDOT), and polythiophene (PTh) . For example, the poly­(vinyl alcohol) nanofibers that have undergone the most effective cross-linking through the incorporation of a conducting polymer, PTh derivatives, exhibited enhanced mechanical resistance to external forces, biocompatibility, water resistance, electrical conductivity, and hydrophobicity . In short, the physicochemical tuning of CPs and multifunctional nanostructure embedded CPs are exceptionally efficient and can be tailored to a particular technique, such as in the context of biomedical or electronic applications.…”

Adhesive Antibacterial Moisturizing Nanostructured Skin Patch for Sustainable Development of Atopic Dermatitis Treatment in Humans

“…Poly­(vinyl alcohol) (PVA) is a water-soluble hydrophilic polymer with low toxicity, high water absorption, impressive mechanical properties, and excellent biocompatibility. , Traditional methods of cross-linking PVA involve the use of high or low temperatures (which can damage sensitive molecules) , or toxic chemicals, such as formaldehyde or glutaraldehyde (which can be irritating and potentially carcinogenic). , Herein, we employed eco-friendly cross-linking of PVA using glycerol (Gly) that can interact through hydrogen bonding, van der Waals forces, and hydrophobic interactions . Green cross-linking offers several benefits compared to traditional approaches, such as (1) eliminating the use of toxic chemicals, reducing the environmental impact and potential health hazards, and (2) operating at room temperature, minimizing the risk of damaging sensitive molecules, or compromising the material’s functionality as well as minimizing the final cost, which beneficially impacts the fabrication scalability.…”

“…16 Poly(vinyl alcohol) (PVA) is a water-soluble, hydrophilic polymer with low toxicity, high water absorption, impressive mechanical properties, and excellent biocompatibility. [17][18] Traditional methods of cross-linking PVA involve the use of high or low temperatures (which can damage sensitive molecules) 19,20 or toxic chemicals, such as formaldehyde or glutaraldehyde (which can be irritating and potentially carcinogenic). 21,22 Herein, we employed eco-friendly cross-linking of PVA using glycerol (Gly) that can interact through hydrogen bonding, van der Waals forces, and hydrophobic interactions.…”