Cellulose acetate conformational changes in various aprotic solvents and the impact on membrane design

• Published in: Cellulose (London) 2024-07, Vol.31 (10), p.6071-6090
• Main Authors: Lanjewar, Shubham, Haldar, Paramita, Acharya, Mihir, Ghosh, Asim K., Moulik, Siddhartha, Roy, Anirban
• Format: Article
• Language: English
• Subjects: Bioorganic Chemistry; cellulose; Cellulose acetate; Ceramics; Chemical bonds; Chemical synthesis; Chemistry; Chemistry and Materials Science; Composites; Dimethyl sulfoxide; Dimethylformamide; Glass; Hollow fiber membranes; Miscibility; Molecular dynamics; Molecular interactions; Natural Materials; Organic Chemistry; Original Research; Phase diagrams; Phase separation; Physical Chemistry; Polymer Sciences; Polymers; Pore formation; porosity; separation; shrinkage; Solvents; Structural stability; Sustainable Development; thermodynamics
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-024-05949-y

This study delves into the macroscopic behavior of cellulose acetate (CA) in three different solvents, namely Dimethyl Formamide (DMF), N-methyl 2-Pyrrolidinone (NMP), and Dimethyl Sulfoxide (DMSO). The combination of experimental studies with molecular dynamics (MD) simulations provides a comprehensive understanding of the intricate molecular interactions and conformational changes governing CA-solvent systems. Practical dimensions are added through investigations into pore formation mechanisms, thermodynamics of phase diagrams, and the synthesis of hollow fiber membranes. The observed de-mixing phenomena varies across solvent systems, with CA-DMSO system undergoing the quickest de-mixing, while CA-NMP demonstrates the slowest. This discrepancy suggests different levels of miscibility and phase separation in distinct solvent environments. Shifts in phase diagrams, along with surface morphology and porosity of synthesized membranes, offer valuable insights into the macroscopic properties of these polymer–solvent systems. MD simulations reveal detailed molecular interactions between CA and each solvent. Structural evolutions, including distortions in bond angles and lengths, showcase unique solvent-specific behaviors. Notably, DMSO induces the highest distortions, while NMP exhibits the least. Studies on radius of gyrations further support these observations, indicating significant structural shrinkage in NMP, sudden shrinkage in DMF, and structural instability with immiscibility in DMSO. These molecular-level findings serve as a bridge to interpret macroscopic properties observed experimentally. The integration of experimental and computational approaches in this study provides a holistic understanding of CA-solvent systems. These insights hold implications for designing and optimizing polymer–solvent systems, particularly in the field of membrane science and technology.