Preparation of ultrafiltration membranes. State of the art

Poly(vinylidene fluoride)/polyethersulfone blend membranes: Effects of solvent sort, polyethersulfone and polyvinylpyrrolidone concentration on their properties and morphology

“…The number of microcell pores increases because there are PVP microcells which exist in the skin layer and PVP may be partially washed out. Secondly, the double diffusion rate of solvent and precipitant is accelerated because of the hydrophibility of PVP [18,19], which results in bigger cavities. Thirdly, the concentration of casting solution increases when PVP is added into the casting solution.…”

Morphological study of poly(vinylidene fluoride) asymmetric membranes: Effects of the solvent, additive, and dope temperature

“…18 Also, the addition of LiCl has been reported to enhance the membrane permeation performance, but with a reduction in its mechanical strength. 18,19 Wang et al, 20 however, managed to retain the membrane mechanical strength by cointroducing 1-propanol. Because of its good water affinity, the presence of LiCl tends to encourage water inflow and enhance the coagulation rate and, therefore, produce membranes with good interconnectivity.…”

SEM analysis and gas permeability test to characterize polysulfone membrane prepared with polyethylene glycol as additive

“…The twophase system is formed from a liquid polymer solution due to addition of a precipitating fluid which is usually miscible with the solvent but immiscible with the polymer. The polymer-rich phase forms the membrane structure while the polymer-poor phase forms the membrane pores [2]. The mechanism of formation of these membranes has been the subject of investigation since many years.…”