Understanding of dielectric properties of cellulose

The theoretical understanding of structural and optoelectronic properties is well-established for a range of inorganic materials; however, such a robust foundation is, in large part, absent in the case of cellulose. Existing literature reports a wide variance in experimentally observed properties for cellulose phases, which are often in contradiction to each other. Motivated by this, we perform an exhaustive first-principles investigation of the structural and optoelectronic properties of cellulose I_α and I_β phases. Utilizing exchange–correlation functionals that accurately describe van der Waals interaction and leveraging state-of-the-art density functional theory methods, we strive to present a highly accurate periodic model for the cellulose phases. We integrate the framework of volume-average theory and the potential impact of water sorption to offer insights into the considerable discrepancies seen across different experimental outcomes. Thus, our study provides a reconciliatory perspective, bridging the gap between theoretical calculations and disparate experimental data.