Fabrication of Robust Waterborne Superamphiphobic Coatings with Antifouling, Heat Insulation, and Anticorrosion

Water-based superamphiphobic coatings that are environmentally friendly have attracted tremendous attention recently, but their performances are severely limited by dispersibility and mechanical durability. Herein, a dispersion of poly(tetrafluoroethylene)/SiO₂@cetyltrimethoxysilane&sodium silicate-modified aluminum tripolyphosphate (PTFE/SiO₂@CTMS&Na₂SiO₃-ATP) superamphiphobic coatings was formed by mechanical dispersion of poly(tetrafluoroethylene) emulsion (PTFE), modified silica emulsion (SiO₂@CTMS), sodium silicate (Na₂SiO₃), and modified aluminum tripolyphosphate (modified ATP). The four kinds of emulsions were mixed together to effectively solve the dispersity of waterborne superamphiphobic coatings. Robust waterborne superamphiphobic coatings were successfully obtained by one-step spraying and curing at 310 °C for 15 min, showing strong adhesive ability (grade 1 according to the GB/T9286), high hardness (6H), superior antifouling performance, excellent impact resistance, high-temperature resistance (<415 °C), anticorrosion (immersion of strong acid and alkali for 120 h), and heat insulation. Remarkably, the prepared coating surface showed superior wear resistance, which can undergo more than 140 abrasion cycles. Moreover, the composite coating with 35.53 wt % SiO₂@CTMS possesses superamphiphobic properties, with contact angles of 160 and 156° toward water and glycerol, respectively. The preparation method of superamphiphobic coatings may be expected to present a strategy for the preparation of multifunctional waterborne superamphiphobic coatings with excellent properties and a simple method.

Robust Waterborne Superhydrophobic Coatings with Reinforced Composite Interfaces

Waterborne superhydrophobic coatings have attracted tremendous attention recently, but their practical applications are severely limited by hydrophobic instability and poor mechanical durability. Herein, a novel robust waterborne PTFE-CP&MgO-AOP superhydrophobic coating was successfully fabricated by reinforcing composite interfaces. Combined with the self-polymerization of dopamine and the in situ grown MgO, CNTs-polydopamine&MgO (CP&MgO) particles with improved interfacial compatibility were obtained. Through the cross-linking and hydrogen bonding interactions, phosphate networks (CP&MgO-AOP) with the aluminum orthophosphate (AOP) binder were formed during dehydration polymerization. The phosphate networks not only enhanced the interfacial interaction among CP&MgO to form coral-like structures but also strengthened the interfacial binding force between the waterborne polytetrafluoroethylene (PTFE) coating and the substrate. With the enhanced composite interfacial strength, the waterborne PTFE-CP&MgO-AOP coating exhibited excellent wear-resistance, which can withstand more than 1.27 × 10⁵ abrasion cycles. Moreover, the chemical bonding between the functional groups of phosphate networks and metal substrate improved the adhesion strength from grade 5 to 1. Furthermore, the prepared coating surface with the reticular/coral-like composite structures can lock the stable gas layer to maintain excellent hydrophobic stability, even under the conditions of strong acidic/alkaline, high-temperature, xenon lamp irradiation, and mechanical wear. Thus, this study is expected to open new insights into interfacial enhancement of robust waterborne superhydrophobic coatings.

Durable Antibacterial Cotton Fabrics Based on Natural Borneol-Derived Anti-MRSA Agents

Borneol, a natural extract with unique bicyclic monoterpene structure, has attracted increasing attention due to its broad-spectrum antibacterial properties via membrane disruption mechanism. However, the negligible water solubility of borneol limits its antibacterial efficiency. Herein, borneol-based water-soluble antibacterial agents are designed and synthesized to combat multi-drug resistant bacteria. The integration of borneol with hydrophilic poly(N,N-dimethylethyl methacrylate) (PDMAEMA) polymer chains boosts the antibacterial capability of borneol against Gram-negative, Gram-positive, and even multi-drug resistant bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) are completely killed upon treatment with 50 µg mL^-1 of borneol-based polymers and Escherichia coli are annihilated at 39 µg mL^-1 . It is further demonstrated that the borneol-based antibacterial agents can be grafted onto cotton fabrics as a nonleaching antibacterial agent, which have higher sustained antibacterial activity than cotton fabrics coated with the commercial quaternary ammonium finishing agents (AEM 5700). The functionalized fabrics with excellent bactericidal activity, especially against MRSA, may have great potential applications in managing hospital-acquired infections.

Polyaniline Anchored MWCNTs on Fabric for High Performance Wearable Ammonia Sensor

Polyaniline (PANI) functionalized multiwall carbon nanotubes (MWCNTs) were prepared via in situ chemical polymerization process of aniline, in which MWCNTs were spray coated on the fabric for wearable ammonia sensor. Structural, morphological, thermal properties and wettability were analyzed by scanning electron microscope, X-ray diffraction, Raman analysis and contact angle measurement. No substantial change in base resistance of MWCNTs/PANI fabric sensor was observed for a wide range of bending (from 90° to 270°) shows excellent wearability. The sensors were exposed to 20-100 ppm ammonia vapor at room temperature. It was observed that the sensing response of PANI coated MWCNTs was enhanced than MWCNTs and PANI. The sensor has the capability to detect ammonia with high sensitivity (92% for100 ppm), excellent selectivity quick response (9 s), and recovery time (30 s). The lower detection limit (LOD) for the MWCNTs/PANI fabric sensor was found to be 200 ppb. The influence of humidity on sensing parameters was studied. Sensing response and resistance of sensor have shown excellent stability after one month. We observed that PANI have a dual role in enhancing flexibility as well as improve the sensor performance toward ammonia. The results reveal the potential application of fabric based sensor for monitoring NH₃ gas under ambient conditions.