Physical Hydrogels of Poly(vinyl alcohol) with Different Syndiotacticity Prepared in the Presence of Lactosilated Chitosan Derivatives

Abstract

Poly(vinyl alcohol) (PVA) physical hydrogels were prepared by repeated freeze–thawing cycles using aqueous solutions of two PVA samples having different degrees of syndiotacticity, a‐PVA and s‐PVA with 55% and 61% of syndiotactic diads, respectively. The hydrogels were prepared in the presence of different amounts of lactosilated chitosan derivatives (LC) of different molecular weight. The PVA stereoregularity was found to have a dramatic effect on the amount of PVA incorporated into the hydrogels, leading to remarkable differences in the swelling degree and porosity of a‐PVA and s‐PVA hydrogels. A significant amount of LC was retained in the hydrogels after equilibrium swelling. The swelling of the a‐PVA hydrogels was found to increase significantly by increasing the amount of LC while it was only slightly increased in the case of s‐PVA hydrogels. The amount of LC released after equilibrium swelling was lower when chitosan derivatives with higher molecular weights were used. Increased initial concentrations of LC resulted in much higher porosity of the hydrogels. TGA and DSC studies showed that LC is stabilized by the incorporation in the PVA hydrogels. The melting temperature of the crystalline regions of PVA was not significantly influenced by LC. Conversely, the extension of the crystalline domains increased in the presence of LC. The retention of a chitosan derivative bearing β‐D‐galactose side chain residues makes these hydrogels potentially useful as scaffolds for hepatocytes culture.Scanning electron micrographs of PVA‐LC hydrogels: (a) a‐PVA; (b) a‐PVA/LC150 80:20; (c) a‐PVA/LC150 50:50.magnified imageScanning electron micrographs of PVA‐LC hydrogels: (a) a‐PVA; (b) a‐PVA/LC150 80:20; (c) a‐PVA/LC150 50:50.

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

“…As discussed above, gelation of PVA is highly tolerant to the presence of added nanoparticles, nanotubes, and emulsion droplets, and these gels accommodate equally well incorporation of macromolecular additives. The latter include a broad spectrum of synthetic and natural polymers, such as DNA,168, 169 chitosan,170, 123 hyaluronic acid,171 and other polymers. Chuang et al124 studied PVA/chitosan blends toward the adhesiveness of the gels to fibroblasts.…”

Structure and properties of hydrogels prepared from cellulose in NaOH/urea aqueous solutions

“…To obtain the network, chemical cross-linking (Denizli, Can, Rzaev, & Guner, 2004;Kiritoshi & Ishihara, 2004;Molina, Gomez-Anton, & Pierola, 2007;Zhao, Liao, Gao, & Liu, 2006), physical entanglement (Saito, Sakurai, Sakakibara, & Saga, 2003), ionic bonds (de la Torre, Torrado, & Torrado, 2003;Kang, Park, Lee, & Son, 2007;Masci, Husu, Murtas, Piozzi, & Crescenzi, 2003;Wong, Díez-Pascual, & Richtering, 2009) and hydrogen bonds (Jin, Liu, Zhang, Chen, & Niu, 2006) are used in the preparation of hydrogels. Polymer hydrogels have been widely utilized as drug delivery, food, cosmetics, high water-absorbing resin, contact lenses, corneal, implant, substitutes for skin, tendons, ligaments, cartilage, and bone, because of their excellent hydrophilicity, permeability, compatibility and low coefficient of friction (Calvert, 2009;Chang, Duan, Cai, & Zhang 2010;Chan, Whitney, & Neufeld, 2009;Liu & Fan, 2005;Yamamoto, Takahashi, & Tabata, 2003).…”

Preparation and characterization of dual responsive sodium alginate‐g‐poly(vinyl alcohol) hydrogel

“…The utilization of PVA in medical and pharmaceutical applications is well documented. 11,12 PVA hydrogel is easily prepared via freezing/thawing cycles. 13,14 This mild procedure has been successfully used to prepare physically cross-linked starch-g-PVA and chitosan-g-PVA hydrogels in our lab.…”