Electrospinning parameters regulate cellulose acetate nanofiber morphology: molecular dynamics simulation study and experimental verification

Abstract

Controlling the morphology of electrospun cellulose acetate (CA) nanofibers is highly dependent on process parameters; however, the molecular-scale physicochemical mechanisms underlying this process remain unclear. Therefore, a combined approach of molecular dynamics simulations and experiments was employed to investigate the microscopic mechanisms of morphology control from the perspectives of hydrogen bond network evolution, molecular chain dynamics, and electric field-induced conformational changes. Both simulation and experimental results indicate that an increase in CA concentration enhances hydrogen bonding and restricts molecular chain motion, contributing to an increase in fiber diameter and a morphological transition from a bead-like to a continuous state; the DMAc/acetone ratio can regulate the equilibrium of hydrogen bonding competition, and when the ratio is 1:2, solvation and molecular entanglement achieve optimal matching; an electric field can induce dynamic hydrogen bond breaking and promote molecular chain extension, thereby achieving fiber refinement. Simulations and experiments consistently show that under conditions of 14 wt% concentration, DMAc/acetone = 1:2, and 20 kV, the hydrogen bond network, molecular chain entanglement, and electric field stretching achieved optimal synergy, resulting in smooth and uniform fiber surfaces with the smallest coefficient of variation in diameter. This study provides insights into the regulatory mechanisms of hydrogen bond networks, molecular chain behavior, and electric field intensity on the morphology of fibers. It not only provides theoretical support and new insights for controlling the preparation of cellulose-based electrospun nanomaterials but also deepens the understanding of the structural relationship between spinning parameters and fiber morphology at the molecular level.