Preparation of a poly(vinyl chloride) ultrafiltration membrane through the combination of thermally induced phase separation and non-solvent-induced phase separation

Fabrication of hierarchically porous superhydrophilic polycaprolactone monolith based on nonsolvent-thermally induced phase separation

Monoliths with a continuous porous structure are of great interest due to high transfer efficiency and large surface area in environmental and tissue engineering fields. This study demonstrated a facile method to prepare PCL monoliths with hierarchically porous structure by nonsolvent-thermally induced phase separation. A suitable mixed solvent mixture using ethanol as nonsolvent reduced the amount of dioxane and provided PCL monoliths with three levels of structures. The monolith structure was easily controlled by changing the fabrication parameters, such as the nonsolvent, the temperature of phase separation, the concentration of the PCL. Finally, the superhydrophilic monolith was easily obtained by polydopamine surface modification. The easy way of fabrication of a hierarchically porous PCL monolith with superhydrophilicity will find applications such as in tissue engineering and purification.

Bioinspired Poly(vinylidene fluoride) Membranes with Directional Release of Therapeutic Essential Oils

Here, the morphology of polypore fungi has inspired the fabrication of poly(vinylidene fluoride) (PVDF) membranes with dual porosity by nonsolvent-induced phase separation (NIPS). The fruiting body of such microorganisms is constituted of two distinct regions, finger- and sponge-like structures, which have been successfully mimicked by controlling the coagulation bath temperature during the NIPS process. The use of water at 10 °C as coagulant resulted in membranes with the highest finger-like/sponge-like ratio (53% of the total membrane thickness), while water at 90 °C allowed the formation of macrovoid-free membranes. The microchannels and the asymmetric porosity were used to enhance the oil sorption capacity of the PVDF membranes and to achieve directional release of therapeutic essential oils. These PVDF membranes with easily tuned asymmetric channel-like porosity and controlled pore size are ideal candidates for drug delivery applications.