A systematic study of the effect of molecular weights of polyvinyl alcohol on polyvinyl alcohol–graphene oxide composite hydrogels

Abstract

Polyvinyl alcohol (PVA) hydrogels have been proposed for use as promising biomaterials in biomedical and tissue engineering, and graphene oxide (GO) has been recognized as a unique two-dimensional building block for various graphene-based supramolecular architectures. In this article, we systematically studied the influence of three kinds of PVA with different molecular weights on the interaction between PVA and GO. Moreover, the effects of PVA on the gelation of GO were also investigated. The native PVA hydrogel, as well as PVA-GO hybrid hydrogels, have been thoroughly characterized by the phase behavior study and various techniques including field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and rheological measurements. It can be seen that with the increase of the molecular weight of PVA, the addition of GO can effectively promote the gelation of PVA which can be reflected by a decrease of the critical gel concentration (CGC) for PVA-GO hydrogels. Dye adsorption experiments indicate that the toxic dye, i.e., methylene blue (MB), was efficiently entrapped in the PVA-GO xerogels. It is also demonstrated that the gelation of PVA and GO composites can be promoted by different supramolecular interactions, including hydrogen bonding and electrostatic interaction. This work indicates that the PVA-GO composite is a good candidate for preparing "super" and "smart" hydrogels and will enable further studies on the supramolecular chemistry of PVA, graphene and its derivatives.

Characterization and Tailoring the Properties of Hydrogels Using Spectroscopic Methods

“…The evolution of the dehydration process can be followed by changes in the vibrational bands corresponding to H-O and C=O bonds of the polymer, but also following the peaks corresponding to water molecules involved in various types of hydrogen bonding. The authors found that the polymer network shrinks with water evaporation and at the end in the gel the residual water forms a tetragonal structure [28]. Similar behaviour on dehydration has been noticed for all polymeric systems [38][39][40].…”

“…IR spectroscopy can be a method for the investigation of these hybrid materials. In a systematic study on the poly(vinyl alcohol) (PVA)/ graphene oxide composite hydrogels, Xue and co-workers [28] noticed that an increase of the PVA molecular weight favours the formation of hydrogels containing GO. GO contains various oxygen functional groups (e.g.…”

“…hydroxyl, epoxide and carbonyl groups) on their basal planes and edges that assure the possibility to be dispersed in water and at the same time to be involved in supramolecular architectures. In such systems, both polar non-covalent interactions and π-π interactions are possible [28,29]. For PVA-GO systems, the FT-IR spectra suggested that oxygen-containing groups on the GO surface possibly interact with the PVA molecules through hydrogen bonding involving the C=O group from the surface of GO and H-O bonds from PVA and water molecules.…”

A Synthetic Hydrogel Composite with the Mechanical Behavior and Durability of Cartilage

“…This increased strength may be attributed to increased hydrogen bonding and entanglement between the polymer chains. [ 60,66 ] However, increasing the molecular weight further to 202 000 g mol −1 lead to a decrease in strength outside of the cartilage‐equivalent range because the higher molecular weight polymer did not fully dissolve during the infiltration processes. Compositions with PVA below 40 wt% were not cartilage equivalent, while higher concentrations did not fully dissolve during infiltration.…”

On the parallelism between the mechanisms behind chromatography and drug delivery: the role of interactions with a stationary phase

“…In this direction, hydrogels are designed in order to obtain mechanical properties suitable to different application in many fields like drug delivery and tissue engineering [3][4][5] . Due to their remarkable characteristics like tunable physical, chemical, and biological properties, high biocompatibility and versatility in fabrication hydrogels have emerged as promising materials in the biomedical field [6][7][8] .…”