Developing Electrospun Ethylcellulose Nanofibrous Webs: An Alternative Approach for Structuring Castor Oil

The development of environment-friendly natural polymer gel-like dispersions in oil media, with functional properties, in terms of formulation design and synthesis protocol, is still a cutting-edge research area for many applications. The aim of this work was to study the manufacture of electrospun ethylcellulose (EC) nanofibrous webs and to examine their usage to thicken vegetable oils as an alternative approach. The role of concentration, molecular weight (M_w), and binary solvent systems on the electrospinnability of EC and subsequently on the rheological properties of EC nanofiber dispersions in castor oil was investigated. It was observed that, for each M_w, defect-free nanofibers were produced above a critical concentration, corresponding to about 2.5 the entanglement concentration (C_e). The average fiber diameter increased with both M_w and EC concentrations. Dielectric constant and dipole moment of binary solvent systems influenced the morphology of the EC nanofiber web. The morphology of the micro- and nanoarchitectures generated played a key role in the physical stabilization and rheological behavior of electrospun EC dispersions. The storage modulus (G') of EC dispersions was correlated with both the spinning solution concentration and average fiber diameter. Furthermore, electrospun EC nanofiber dispersions were compared with EC oleogels obtained by traditional thermogelation from thermorheological and tribological points of view. Overall, this work proposes an efficient and innovative approach to produce bio-based oleogel-like dispersions with great potential in different sectors such as pharmaceuticals, food, or lubricants.