Asymmetric Sc-PLA Membrane with Multi-scale Microstructures: Wettability, Antifouling, and Oil–Water Separation

Abstract

In this work, an eco-friendly superhydrophobic stereo-complex polylactic acid (Sc-PLA) membrane was fabricated by a facile non-solvent-induced phase separation (NIPS) method, followed by peeling off its skin layer. By adjusting the thickness and roughness, membranes with various multi-scale microstructures could be obtained due to the formation of stereo-complex crystals during the process of phase separation. The Sc-PLA membranes display a hydrophobic wetting property. Interestingly, when the skin layer of the membrane with a 600 μm thickness was peeled off, the water contact angle on the surface of the membrane significantly improved from 142 to 152°, and the membrane displayed superhydrophobic wetting properties, which may be owing to the improvement of roughness for the surface by enlarging the exposure opportunity of finger holes and microstructures. In addition, the Sc-PLA membrane with superhydrophobicity shows excellent antifouling performance and large oil absorption capacity. Predictably, the Sc-PLA membranes may have potential applications in antifouling and oil-water separation.

Super High‐Expansion Poly(Lactic Acid) Foams with Excellent Oil‐Adsorption and Thermal‐Insulation Properties Fabricated by Supercritical CO2 Foaming

“…The types and approximate densities of oils are listed in Table S1, Supporting Information. In Figure 9c, the biopolymers include PLA, [ 17,41,52–56 ] cotton fabric, [ 57 ] poly(vinyl alcohol), [ 58 ] chitin, [ 59 ] cellulose, [ 60,61 ] lettuce, [ 62 ] and osmanthus flowers. [ 63 ] In Figure 9d, the traditional petroleum‐based polymers include polypropylene, [ 64 ] polyethylene, [ 65–67 ] polycarbonate, [ 68,69 ] polystyrene, [ 70,71 ] thermoplastic polyurethane, [ 72 ] and poly(vinylidene fluoride).…”

“…Figure 9c,d present the comparison of adsorption capacity of the PLA open-cell foam prepared herein and the oil-adsorption materials based on biopolymers [17,41,[52][53][54][55][56][57][58][59][60][61][62][63] and traditional petroleum-based polymers [64][65][66][67][68][69][70][71][72][73][74] reported in the literatures for various oils with different densities, respectively. The types and approximate densities of oils are listed in Table S1, Supporting Information.…”

“…This indicates that the PLA open-cell foam exhibits strong oiladsorption ability. It should be pointed out that the above oil-adsorption materials are mostly prepared through phase separation, [41,[52][53][54][55]60] freeze-drying, [59] solution spinning, [56] and surface modification. [57][58][59]61,62] In these preparation processes, toxic organic solvents or chemical reagents are usually used, easily causing secondary environmental pollution and endangering human health.…”

Tailoring of advanced poly(lactic acid)‐based materials: A review

“…The air‐drying process was reported for drying of PLA films after solvent casting and scaffolds after solvent replacement 117,119,121,153,154 . When used for scaffold preparation, method does not preserves the porous gel structure upon solvent removal.…”

“…The first step in gel preparation is the selection of an appropriate solvent. Different organic solvents have been reported for preparation of PLA solutions such as chloroform (CHL), 10,59,118,119,147,148,169 tetrahydrofuran (THF), 3,121,147 dichloromethane (DCM), 11,123,127,133,147 ethyl lactate (EL), 130,131 dimethylformamide (DMF), 147,175 dimethylacetamide (DMA), 147 N ‐methyl pyrrolidone, 154 and 1,4‐dioxane (DX) 2,34,129,147 . Beside dissolution in a single solvent, PLA was also dissolved in binary 4,25,147,150,174 and triple solvent systems 149 .…”