Stimulus-Responsive Biopolymeric Surface: Molecular Switches for Oil/Water Separation

Abstract

In this work, we fabricated a stimulusresponsive biopolymeric material and demonstrated the reversible character of a hydrophilic/hydrophobic interface upon exposure to UV light. Importantly, this stimulusresponsive material exhibited excellent features in an oil/ water separation system. Cellulose was functionalized on both sides of the surface with a dopamine polymer and further modified with an azobenzene-fluorosilane material. Azobenzene can alter the properties of a material via an isomerization effect (trans−cis) upon exposure to UV light. Initially, the azobenzene-fluorosilane material was in a hydrophobic state; the contact angle was over 130°; and absorption performance with various organic solvents showed there to be high levels of extractive activity and outstanding reusability. When we exposed the material to UV light, the surface changed to that of a hydrophilic nature, and this phenomenon was influenced by the azobenzene chemistry of folding and unfolding of an azobenzene-fluorosilane molecule. Significantly, this phenomenon is a reversible, reusable, and eco-friendly material. Furthermore, dopamine polymers could block organic material, bacteria, and fungi, and this surface can be used for wastewater purification. Therefore, we foresee that the stimulus-responsive surface of biopolymeric material could result in a different direction in the oil/water purification fields.

Carbon Nanotubes and Polydopamine Modified Poly(dimethylsiloxane) Sponges for Efficient Oil–Water Separation

“…The element distribution of PDA/CNT-PDMS is shown in Figure S5 , where the presence of N element proves that PDA has deposited on the CNT-PDMS sponge as well. With the introduction of PDA, the surface of PDA/PDMS and PDA/CNT-PDMS transform into super-hydrophilicity (water contact angle <5°, inset in Figure 2 (c 1 ,d 1 )), which can be ascribed to the cooperation effect of hydrophilic PDA and high roughness from the porous structure [ 34 ].…”

Approaches to Preceramic Polymer Fiber Fabrication and On-Demand Applications

“…Surface modification via the silanization method can be performed on powder or solid material. The widely used reagent for the silanization process is organic silane, which can create a monolayer assembly on the surfaces [93][94][95][96][97][98][99][100]. The surface-modified material can enhance and stimulate adhesion to surface/materials.…”

Engineering a Biopolymer-Based Ultrafast Permeable Aerogel Membrane Decorated with Task-Specific Fe–Al Nanocomposites for Robust Water Purification

“…While nanotechnology promises to provide smaller and more effective devices and processes, immobilizing active nanosites having greater contact with the pollutants has always been a main concern, besides leaky distribution and tedious regeneration process, which limits their applicability toward real-water treatment . Besides active inorganic nanomaterials, engineered biomaterials have also been examined for the abatement of dyes, fluoride, and arsenic from water. , Biopolymers are ubiquitous in advanced water purification technologies owing to their exceptional properties and have found widespread application in ultrafiltration and oil–water separations. , On the other side, some chitosan-based aluminum and iron composites were explored as efficient adsorbents for arsenic and fluoride removal from an aqueous medium but have limitations to discrete water systems. , Currently, adsorption-based membranes or hybrid membranes are emerging as a panacea for water-related problems and show efficient removal of dyes and fluoride from contaminated water with high rejection and improved flux. , However, high-cost materials, flexibility for diversified pollutants, and low water permeability restrict their large-scale utility. Thus, development of a cost-effective protocol for rapid and versatile water purification is of utmost importance.…”

“…Herein, a novel biopolymer-based aerogel membrane doped with α-FeOOH and γ-AlOOH nanocomposites has been designed and fabricated for sustainable and robust water purification with ultrafast water permeability. Among the several biopolymers used in water treatment, chitosan-based composites have been extensively employed because of their sustainability and antimicrobial nature. , Likewise, agarose, a polysaccharide, undergoes gelation through the formation of extensive intermolecular hydrogen bonding, resulting in double-helical structures that aggregate into thick bundles . A combination of chitosan and agarose assisted by ethylenediaminetetraacetate dianhydride (EDTAD) leads to a stable superhydrophilic aerogel even in harsh conditions (pH and temperature).…”