Significance of thermodynamics and rheological characteristics of dope solutions on the morphological evolution of polyethersulfone ultrafiltration membranes

Abstract

Herein, the effect of solvent type and polymer concentration on the thermodynamic and viscoelastic properties, and performance of polyethersulfone (PES) ultrafiltration (UF) membranes are investigated. The morphology and mechanical properties of the membranes are examined too. Rheological measurements indicated that solidification and instantaneous demixing occurred fast for PES/N‐methyl‐2‐pyrrolidone (NMP) dope solution. This resulted in a dense skin layer with a finger‐like structure confirmed by the scanning electron microscopy images. In comparison, PES/dimethylformamide (DMF) exhibited a delayed solidification and demixing with a sponge‐like structure. Rheological characteristics and ternary phase diagrams of two systems are examined to gain insights and make correlations with the morphology of resultant membranes. Performance analysis revealed that membranes derived from PES/NMP system exhibited both improved pure water flux and bovine serum albumin rejection suggesting the superiority of NMP compared to DMF as the solvent of choice for the preparation of PES UF membranes.

Tailoring the Morphology and Performance of Polyacrylonitrile Ultrafiltration Membranes for Produced Water Treatment via Solvent Mixture Strategy

“…Therefore, determining an optimal polymer concentration and an appropriate solvent can be highly crucial for improving the membrane morphology and performance [42]. The cloud point for each dope solution was measured via titration by the non-solvent based on the transformation of the solutions into turbidity [43,44]. For doing so, polymer solutions containing PAN at 1, 3, 5, 10, 15, 20, and 25 wt % in DMF and NMP were prepared and titrated at 25 °C by dropwise addition of water into each solution.…”

Poly(ethylene terephthalate) phase inversion membranes: Thermodynamics and effects of a poor solvent on the membrane characteristics

“…Systems with a larger miscibility gap (separation between P-S axis and cloud point curve) exhibit a higher probability of macrovoid formation. [65,66]…”

Design, preparation, and characterization of silk fibroin/carboxymethyl cellulose wound dressing for skin tissue regeneration applications

“…[2] Therefore, the importance of wound healing, especially for people who are diabetics, who are at high risk of wound infection, has received much attention. [3][4][5][6][7][8] Hence, using the best treatment method with a full understanding of the wound healing process helps to minimize infection at the lesion site and brings us closer to a successful wound healing. [3,9,10] The first step to protecting a skin lesion is to cover it with a dressing to prevent entering any foreign agents and keep the wound site clean.…”

“…[3][4][5][6][7][8] Hence, using the best treatment method with a full understanding of the wound healing process helps to minimize infection at the lesion site and brings us closer to a successful wound healing. [3,9,10] The first step to protecting a skin lesion is to cover it with a dressing to prevent entering any foreign agents and keep the wound site clean. [11,12] To date, different types of wound dressings have been produced.…”

“…[ 3‐8 ] Hence, using the best treatment method with a full understanding of the wound healing process helps to minimize infection at the lesion site and brings us closer to a successful wound healing. [ 3,9,10 ]…”