Title
In vitro preparation of self-assembled super-swollen hydrogels from solutions of lignocellulose in NN-dimethylacetamide/lithium chloride
Authors
NINA KOTELNIKOVA ALEKSANDRA MIKHAILIDI YULIYA MARTAKOVA and SEPPO ANDERSSON

Received Dedicated to the memory of Acad. Prof. Cr. I. Simionescu
Published Volume 50 Issue 5-6 May-June
Keywords lignocelluloses, solutions, DMAc/LiCl, self-assembly, hydrogels

Abstract
Stable super-swollen hydrogels were prepared in vitro from powder lignocelluloses of various origins via direct dissolution in DMAc/LiCl, followed by subsequent regeneration from the solutions. The main properties of the swollen hydrogels, such as equilibrium solvent content, porosity and dye uptake, were determined. The hydrogels retained large amounts of water (up to 2500 wt%), had high porosity and specific surface areas. The superabsorbance of the hydrogels was confirmed by WAXS results. The hydrogels seem to be “smart” matters due to their pH-dependent behaviour, as demonstrated by swelling experiments. The formation of hydrogels occured via spontaneous self-assembly from the solutions and due to the reconstruction of a new hydrogen bond web between the lignocellulose chains and the water. The hydrogels were stable, but crucially changed their morphology after drying, because of water removal and collapse of the H-bonds formed. These findings demonstrate that the lignocellulose hydrogels are novel attractive materials that will find potential applications in a wide range of fields.