Durable superhydrophobic/superoleophilic PDMS sponges and their applications in selective oil absorption and in plugging oil leakages

Abstract

A facile method for preparing porous polydimethylsiloxane (PDMS) sponges is reported. The PDMS sponges are fabricated by the polymerization of the PDMS prepolymer and a curing agent in dimethicone using NaCl microparticles as the hard templates. The porous structure of the PDMS sponges is controllable simply by regulating the weight ratio of prepolymer to dimethicone and the size of the NaCl microparticles. The PDMS sponges feature high compressibility and stretchability, excellent superhydrophobicity/superoleophilicity, as well as high chemical and thermal stability. The PDMS sponge can completely recover its original shape even after 50 cycles of 90% strain. The elongation at breaking the sponge is as high as 97%. The PDMS sponge is superhydrophobic with a water contact angle of 151.5 but can be easily wetted by oils.The sponge also exhibits excellent repellency to corrosive aqueous liquids. The flexibility and superhydrophobicity of the sponge remain unchanged even after keeping in liquid nitrogen or at 250 C for 24 h. Long-term immersion in various organics has no obvious influence on superhydrophobicity, oil absorbency, or weight of the sponge. The PDMS sponge can selectively absorb a large amount of floating oils on the water surface and heavy oils under the water, and furthermore, is reusable. Moreover, the PDMS sponge swells quickly after the adsorption of oils, which makes it a promising material for plugging oil leakages.

A Robust Cu(OH)2 Nanoneedles Mesh with Tunable Wettability for Nonaqueous Multiphase Liquid Separation

“…Among various liquids separation methods, membrane technique is regarded as a low-cost, effective, and environment friendly choice that has drawn considerable interest in last decade. Since the idea of taking the special wettability surface into the application of oil/water separation was proposed, [ 1 ] the researchers have prepared a large number of materials for the separation of oil/water mixtures.[ 2-6 ] Such as nanofi ber textile, [7][8][9][10] 3D porous foams, [11][12][13][14][15][16] and mesh [17][18][19][20][21] were frequently used to achieve water/oil separation. Nonetheless, water/oil separation system cannot satisfy the complex liquid mixture requirement during real industry processes.…”

Versatile fabrication of magnetic carbon fiber aerogel applied for bidirectional oil–water separation

“…Recently, functional materials with opposite wetting behavior to water and oil liquids are considered to be promising candidates for oil-water separation, due to their high selectivity. The materials selected are including carbon-based three-dimensional (3D) frameworks with porous structures [4][5][6][7][8][9][10][11][12][13], mesh films [14][15][16], and sponges [6,9,13,[17][18][19]. For example, Pan et al fabricated superhydrophobic magnetic foams used for oil removal by pyrolyzing commercial polyurethane sponge grafted with polyelectrolyte layers at 400°C [9].…”

Recent Advances in the Fabrication of Superhydrophobic Surfaces

“…to create appropriate roughness for coating. 9,16,2325,28 In addition, during the preparation process, it is worth mentioning that, when the prepared materials are coated on the substrate, the corresponding chemical reaction or ordered action may occur such as polymerization, 36 grafting, 74 self-assembly, 16 in situ growth, 26,27,75 and so on. Utilizing these actions, we can obtain expectable superhydrophobic coatings for a wide number of applications.…”

“…On the one hand, the effective methods to create appropriate roughness include electrodeposition, 915 chemical deposition, 1620 etching, 2125 in situ growth, 26,27 plasma process, 28 boiling water treatment, 29 and so on. On the other hand, the modification methods to decrease the surface energy include solution immersion, 3034 heat treatment, 13 electrodeposition, 1012,15 chemical vapor deposition, 14,20,22,28,35 polymerization on the substrate, 36 etc. Here, it is worth mentioning that the surface energy of one certain surface is an explicit value, which is decided by the substance forming the surface.…”

“…are all often used as modification materials. Inspired by perfect special wettability in nature, various kinds of superhydrophobic surfaces have been fabricated for practical applications, including anticorrosion metals, 9,37 waterproof fabrics, 23 sponges and meshes or other hard substrates for oil/water separation, 36,3840 self-cleaning surfaces, 4144 and so on. To achieve some practical applications, superhydrophobicity has been combined with other performance to achieve multifunctional materials such as responsive materials, 45 transparent superhydrophobic surfaces, 46 and selfhealing superhydrophobic surfaces.…”