Superhydrophobic Coatings Prepared by the in Situ Growth of Silicone Nanofilaments on Alkali-Activated Geopolymers Surface

Abstract

As a highly hydrophobic and good environmental durable material, silicone nanofilaments have shown great advantages in the construction of superhydrophobic coatings. However, the synthesis of these materials has always been limited to the application of trifunctional organosilane monomers under the action of acidic catalysts. For the first time, long-chain polymeric hydrogenated siloxane-poly­(methyl-hydrosiloxane) (PMHS) was used to synthesize rapidly silicone nanofilaments in situ under alkaline conditions. A dense silicone nanofilament coating was obtained by PMHS + geopolymer layer on a smooth iron sheet, and achieved by one-step brushing of PMHS on the surface of a just-solidified alkali-activated metakaolin-based geopolymer coating at 120 °C for an hour of sealed curing. This composite coating was followed by a superhydrophobic composite coating with a contact angle of approximately 161° and a rolling angle of 2°. Consistent with this, laser scanning confocal microscopy and field-emission scanning electron microscopy images show the presence of micro- and nanoscale features that enable the entrapment of air when exposed to water and endow excellent superhydrophobic properties. Because geopolymer material has good adhesion ability with metal, ceramic, or other materials, the composite superhydrophobic coating is expected to be widely used.

A Facile Method for Preparing Superhydrophobic and Flame‐Retardant Fabrics Materials

“…Figure 1B shows the reaction at a fixed wavenumber of 2166 cm −1 , corresponding to the SiH bond of the reaction core in PMHS. [ 21 ] When the reaction progressed to 23 min, the trend in the absorbance changed from a decrease to a smooth plateau, which means that the SiH bond in the system disappeared; in other words, the PMHS hydrolysis was completed.…”

Functional Catechol–Metal Polymers via Interfacial Polymerization for Applications in Water Purification

“…The polymers with dodecyl side chains, P2 and P2′ showed high superhydrophobicity with a contact angle >160°, as the drop refused to adhere over the surface (Figures and ; SI Videos S1 and S2). Control experiments were done using filter paper showed high hydrophilicity and wettability with a contact angle of 0°. For our polymers, the hydrophobicity of the film increased with increase in length of the substituents on the catechol ligand.…”

“…The drop deformed on contact with the substrate and departed from the surface indicating superhydrophobicity (Figure ). , The experiment was repeated by increasing the size of the droplet (5 μL) to provide more surface area of water droplet for making contact with the coated substrate and to introduce gravitational force, but the drop did not adhere to the surface after making contact (SI Video S3). , We did not increase the drop size further because of risk of getting false contact angle due to flattening of drop owing to its increased weight and gravitational pull, especially at very high contact angles. , When the water drop was released from the syringe head, it bounced and deflected from the surface to the other side owing to its poor adherence to the substrate at a very low sliding angle <10° (SI Video S4).…”

Natural Fibers as an Alternative to Synthetic Fibers in Reinforcement of Geopolymer Matrices: A Comparative Review

“…The resistance 13 of this type of interaction depends on the type and number of chemical bonds per unit area. Coupling agents are often used for this type of adhesion to occur, such as silanes, which are commonly used by coupling oxide groups on the surface of the glass to bond with molecules of polymeric matrices [ 68 ]. At one end (A) of the silane molecule, hydrogen bonds are formed between the oxide groups on the glass and the partially hydrolyzed silane, as the other end (B) reacts with a compatible group on the polymer ( Figure 2 d) [ 69 ].…”