Honeycomb structured membranes from cellulose–polystyrene composites: quantitative evaluation of casting parameters and membrane ordering

Abstract Honeycomb-structured membranes are emerging as highly functional materials for applications in separation, biomedical engineering, and surface coatings. However, efforts to incorporate cellulose into these membranes have been limited by its poor solubility. This work explored two sustainable strategies to integrate cellulose into honeycomb membranes: physical mixing and in-situ composite formation with polystyrene (PS). Specifically, commercial microcrystalline cellulose (MCC) and cellulose extracted from Gelidium sp . algae ( Celb ) were used to generate PS-cellulose blends and composites. Membranes with mono-, bi- and multilayers of interconnected or non-interconnected pores were fabricated under controlled casting environments that varied relative humidity (RH), air flow, and surface preconditioning. Structural order and pore arrangement were quantitatively analyzed via a combined metric of the two parameters span (σ) and theta (θ) from a virtual light scattering method. Among the tested formulations, the composites consistently produced more regular porous structures than the mixtures. Notably, Com1 (PS–MCC composite) formed the most ordered membranes under 95% RH and wet surface conditions without airflow. Meanwhile, Com2 (PS– Celb composite) showed a broader performance range and greater sensitivity to casting parameters. These findings demonstrate the feasibility of quantitatively assessing film quality and producing cellulose-based honeycomb membranes without chemical modification, offering a promising pathway toward scalable, sustainable, and tunable membrane materials. Graphical abstract