Production and microstructure-property correlations in mono-oriented bacterial cellulose membranes

Abstract

The development of naturally occurring biodegradable materials has increasingly attracted the attention of researchers in recent years owing to the rising environmental concern. Among these materials, bacterial cellulose (BC) stands out as an easily obtainable polysaccharide mat with potential for application in several areas. Nanocelluloses, regardless of origin, are known to form gels in aqueous systems that, when dried, consolidate into materials stabilized both by the entanglements themselves and by hydrogen bonds between adjacent particles, the latter strongly dependent on the degree of interfibrillar orientation. Because of the above, this research aims to promote mechanical anisotropy at different levels through the preferential orientation of BC nanofibrils, achieved by asymmetric drying. The BC membrane was dried either in a “free” or “restricted” fashion within an atmosphere of controlled temperature and relative humidity. Different degrees of pre-stretching were also investigated to enhance the mechanical resistance and stiffness in the direction of the drying restriction. The resulting materials will be characterized concerning morphology, structure, and mechanical properties through scanning electron microscopy, polarized infrared spectroscopy, polarized optical microscopy, X-ray diffraction, and dynamicmechanical thermal analysis. Promising conditions and potential applications will also be discussed and analyzed.