A Robust Biomimetic Superhydrophobic Coating with Superior Mechanical Durability and Chemical Stability for Inner Pipeline Protection.

Durable superhydrophobic anti-erosion/anticorrosion coatings are highly demanded across various applications. However, achieving coatings with exceptional superhydrophobicity, mechanical strength, and corrosion resistance remains a grand challenge. Herein, a robust microstructure coating, inspired by the cylindrical structures situated on the surface of conch shell, for mitigating erosion and corrosion damages in gas transportation pipelines is reported. Specifically, citric acid monohydrate as a pore-forming agent is leveraged to create a porous structure between layers, effectively buffering the impact on the surface. As a result, the coating demonstrates remarkable wear resistance and water repellency. Importantly, even after abrasion by sandpaper and an erosion loop test, the resulting superhydrophobic surfaces retain the water repellency. The design strategy offers a promising route to manufacturing multifunctional materials with desired features and structural complexities, thereby enabling effective self-cleaning and antifouling abilities in harsh operating environments for an array of applications, including self-cleaning windows, antifouling coatings for medical devices, and anti-erosion/anticorrosion protection, among other areas.

Recent advances in conductive hydrogels: classifications, properties, and applications.

Hydrogel-based conductive materials for smart wearable devices have attracted increasing attention due to their excellent flexibility, versatility, and outstanding biocompatibility. This review presents the recent advances in multifunctional conductive hydrogels for electronic devices. First, conductive hydrogels with different components are discussed, including pure single network hydrogels based on conductive polymers, single network hydrogels with additional conductive additives (i.e., nanoparticles, nanowires, and nanosheets), double network hydrogels based on conductive polymers, and double network hydrogels with additional conductive additives. Second, conductive hydrogels with a variety of functionalities, including self-healing, super toughness, self-growing, adhesive, anti-swelling, antibacterial, structural color, hydrophobic, anti-freezing, shape memory and external stimulus responsiveness are introduced in detail. Third, the applications of hydrogels in flexible devices are illustrated (i.e., strain sensors, supercapacitors, touch panels, triboelectric nanogenerator, bioelectronic devices, and robot). Next, the current challenges facing hydrogels are summarized. Finally, an imaginative but reasonable outlook is given, which aims to drive further development in the future.

Superhydrophobic polyurethane sponge for efficient water-oil emulsion separation and rapid solar-assisted highly viscous crude oil adsorption and recovery.

Rapid and efficient cleaning of oily wastewater and high viscosity crude oil spills is still a global challenge. Conventional three-dimensional porous adsorbents are ineffective for oil-water separation in harsh environment and are restricted to the low fluidity of high viscosity crude oil at room temperature. Increasing temperature can enormously improve the fluidity of viscous crude oil. Herein, the polydimethylsiloxane (PDMS) /carbon black (CB) -modified polyurethane sponge (PU) were prepared by a simple one-step dip-coating method. PDMS/CB@PU (PCPU) exhibits high adsorption capacity to various oils and organic liquid (28.5-68.7 g/g), strong mechanical properties (500 cycles at 50%), outstanding reusability (100 cycles of adsorption and desorption) and excellent environmental stability due to the special PDMS/CB coating. The maximum surface temperature of PCPU sponge can reach 84.7 â„ƒ under 1 sunlight irradiation. Therefore, the PCPU sponge can rapidly heat and enhance the fluidity of viscous crude oil, significantly speeding up the viscous oil recovery process with the maximum adsorption capacity of 44.7 g/g. In addition, the PCPU sponge can also combine with the vacuum pump to realize the continuous and rapid repair of viscous oil spills from the seawater surface. In consideration of its simple preparation, cost-effectiveness and high oil absorption ability, this solar-assisted self-heating adsorbent provides a new direction for large-scale cleanup and recycling of viscous crude oil spill on the seawater surface.

A Breathable Knitted Fabric-Based Smart System with Enhanced Superhydrophobicity for Drowning Alarming.

Wearable strain sensors have aroused increasing interest in human motion monitoring, even for the detection of small physiological signals such as joint movement and pulse. Stable monitoring of underwater human motion for a long time is still a notable challenge, as electronic devices can lose their effectiveness in a wet environment. In this study, a superhydrophobic and conductive knitted polyester fabric-based strain sensor was fabricated via dip coating of graphene oxide and polydimethylsiloxane micro/nanoparticles. The water contact angle of the obtained sample was 156°, which was retained above 150° under deformation (stretched to twice the original length or bent to 80°). Additionally, the sample exhibited satisfactory mechanical stability in terms of superhydrophobicity and conductivity after 300 abrasion cycles and 20 accelerated washing cycles. In terms of sensing performance, the strain sensor showed a rapid and obvious response to different deformations such as water vibration, underwater finger bending, and droplet shock. With the good combination of superhydrophobicity and conductivity, as well as the wearability and stretchability of the knitted polyester fabric, this wireless strain sensor connected with Bluetooth can allow for the remote monitoring of water sports, e.g., swimming, and can raise an alert under drowning conditions.

In Situ Growth of a Stable Metal-Organic Framework (MOF) on Flexible Fabric via a Layer-by-Layer Strategy for Versatile Applications.

Fabrics have been used broadly in daily life for an enormous variety of applications due to their intrinsic advantages, such as flexibility, renewability, and good processability. Integrating natural fabrics with metal-organic frameworks (MOFs) is an effective strategy to improve the added value of textiles with special functionalities. Here, a facile, low-cost, and scalable technology is reported for the in situ growth of MOFs on cotton fabrics. A uniform and dense coating of regular octahedral Cu-1,3,5-benzenetricarboxylic acid (CuBTC) crystals was formed on the fiber surface, followed by treatment with 1H,1H,2H,2H-perfluorooctyltriethoxysilane and triethoxyoctylsilane to create a superhydrophobic CuBTC@cotton fabric (SMCF), which greatly improved its water stability and extended superhydrophobic CuBTC's potential applications. The as-prepared MCF has a specific surface area of 229 m2/g, which is 11 times that of pristine fabrics (21 m2/g). This high porosity further endows the fabric with enhanced loading capacity of essential oils to enable excellent antibacterial ability. Moreover, the SMCF also exhibits excellent self-cleaning, UV shielding, and anti-icing performances. In addition, we performed COMSOL simulations to investigate the dynamic freezing process of water on the surface of samples, which agrees well with our experimental observations. By combining the merits of both fabrics and MOFs, the MCF is expected to extend the applications of traditional textiles in antifouling, safety, the fragrance industry, and healthcare for the next-generation multifunctional fabrics.

Functionalized Fiber-Based Strain Sensors: Pathway to Next-Generation Wearable Electronics.

Wearable strain sensors are arousing increasing research interests in recent years on account of their potentials in motion detection, personal and public healthcare, future entertainment, man-machine interaction, artificial intelligence, and so forth. Much research has focused on fiber-based sensors due to the appealing performance of fibers, including processing flexibility, wearing comfortability, outstanding lifetime and serviceability, low-cost and large-scale capacity. Herein, we review the latest advances in functionalization and device fabrication of fiber materials toward applications in fiber-based wearable strain sensors. We describe the approaches for preparing conductive fibers such as spinning, surface modification, and structural transformation. We also introduce the fabrication and sensing mechanisms of state-of-the-art sensors and analyze their merits and demerits. The applications toward motion detection, healthcare, man-machine interaction, future entertainment, and multifunctional sensing are summarized with typical examples. We finally critically analyze tough challenges and future remarks of fiber-based strain sensors, aiming to implement them in real applications.

Robust Superhydrophobic rGO/PPy/PDMS Coatings on a Polyurethane Sponge for Underwater Pressure and Temperature Sensing.

Flexible wearable pressure sensors have attracted great interest from researchers in recent years because of their important applications in human-machine interaction, human behavior detection, medical diagnosis, and other fields. At present, integrating multiple functions such as pressure and temperature sensing and self-cleaning into a single material remains a challenging task. Here, by in situ reduction of graphene oxide (GO) grown on a sponge surface and deposition of polypyrrole (PPy) nanoparticles, we have built a highly sensitive, stable, and multifunctional rGO/PPy/poly(dimethylsiloxane) (PDMS) polyurethane (PU) sponge (GPPS) sensor for the detection of pressure, water level, and temperature. This multifunctional sensor shows excellent pressure-sensing performance, ultrasensitive loading sensing of a leaf (98 mg), and outstanding reproducibility over 5000 cycles. Due to the stability of the superhydrophobic surface water contact angle (WCA) = 153.3°, our sensor can work in an underwater environment, which can sense water levels from 1 cm (∼98 Pa) to 40 cm and also a variety of underwater behaviors (knock, ultrasonication, blow, etc.) with high stability. In addition, the sensor can be integrated into a circuit for the water level and pressure detection. The sensor can also be used as a smart underwater-temperature sensor; it shows a linear temperature coefficient of resistance (TCR) of 0.48% °C-1 in a temperature range of 35-80 °C. This multifunctional sensor shows potential application prospects in wearable electronic devices for sensing.

Bioinspired Soot-Deposited Janus Fabrics for Sustainable Solar Steam Generation with Salt-Rejection.

Inspired by lotus leaves, self-floating Janus cotton fabric is successfully fabricated for solar steam generation with salt-rejecting property. The layer-selective soot-deposited fabrics not only act as a solar absorber but also provide the required superhydrophobicity for floating on the water. With a polyester protector, the prepared Janus evaporator exhibits a sustainable evaporation rate of 1.375 kW m-2 h-1 and an efficiency of 86.3% under 1 sun (1 kW m-2) and also performs well under low intensity and inclined radiation. Furthermore, no special apparatus and/or tedious processes are needed for preparing this device. With a cost of less than $1 per m2, this flexible Janus absorber is a promising tool for portable solar vapor generator.

Durable antibacterial and UV-protective Ag/TiO2@ fabrics for sustainable biomedical application.

A facile method was developed to endow cotton fabric with remarkable antibacterial and ultraviolet (UV)-protective properties. The flower-like TiO2 micro-nanoparticles were first deposited onto cotton fabric surface via hydrothermal deposition method. Then, the Ag NPs with a high deposition density were evenly formed onto TiO2@cotton surface by sodium hydroxide solution pretreatment and followed by in situ reduction of ANO3. This work focused on the influence of different hydrothermal reaction durations and the concentration of AgNO3 on antibacterial activity against relevant microorganisms in medicine as well as on the UV-blocking property. Ag NPs-loaded TiO2@cotton exhibited high antibacterial activity with an inhibition rate higher than 99% against Staphylococcus aureus and Escherichia coli bacteria. Moreover, the as-prepared cotton fabric coated with Ag NPs and TiO2 NPs demonstrated outstanding UV protective ability with a high ultraviolet protection factor value of 56.39. Morphological image of the cells revealed a likely loss of viability as a result of the synergistically biocidal effects of TiO2 and Ag on attached bacteria. These results demonstrate a facile and robust synthesis technology for fabricating multifunctional textiles with a promising biocidal activity against common Gram-negative and Gram-positive bacteria.

Recent Progress in Fabrication and Applications of Superhydrophobic Coating on Cellulose-Based Substrates.

Multifuntional fabrics with special wettability have attracted a lot of interest in both fundamental research and industry applications over the last two decades. In this review, recent progress of various kinds of approaches and strategies to construct super-antiwetting coating on cellulose-based substrates (fabrics and paper) has been discussed in detail. We focus on the significant applications related to artificial superhydrophobic fabrics with special wettability and controllable adhesion, e.g., oil-water separation, self-cleaning, asymmetric/anisotropic wetting for microfluidic manipulation, air/liquid directional gating, and micro-template for patterning. In addition to the anti-wetting properties and promising applications, particular attention is paid to coating durability and other incorporated functionalities, e.g., air permeability, UV-shielding, photocatalytic self-cleaning, self-healing and patterned antiwetting properties. Finally, the existing difficulties and future prospects of this traditional and developing field are briefly proposed and discussed.