Kesong Liu

Recent developments in bio-inspired special wettability.

Nature is a school for scientists and engineers. After four and a half billion years of stringent evolution, some creatures in nature exhibit fascinating surface wettability. Biomimetics, mimicking nature for engineering solutions, provides a model for the development of functional surfaces with special wettability. Recently, bio-inspired special wetting surfaces have attracted wide scientific attention for both fundamental research and practical applications, which has become an increasingly hot research topic. This Critical Review summarizes the recent work in bio-inspired special wettability, with a focus on lotus leaf inspired self-cleaning surfaces, plants and insects inspired anisotropic superhydrophobic surfaces, mosquito eyes inspired superhydrophobic antifogging coatings, insects inspired superhydrophobic antireflection coatings, rose petals and gecko feet inspired high adhesive superhydrophobic surfaces, bio-inspired water collecting surfaces, and superlyophobic surfaces, with particular focus on the last two years. The research prospects and directions of this rapidly developing field are also briefly addressed (159 references).

Bioinspired Surfaces with Superwettability: New Insight on Theory, Design, and Applications

Design, and Applications Shutao Wang,†,‡ Kesong Liu, Xi Yao, and Lei Jiang*,†,‡,§ †Laboratory of Bio-inspired Smart Interface Science, Technical Institute of Physics and Chemistry, and ‡Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, BeiHang University, Beijing 100191, People’s Republic of China Department of Biomedical Sciences, City University of Hong Kong, Hong Kong P6903, People’s Republic of China

Bio-Inspired Titanium Dioxide Materials with Special Wettability and Their Applications

Their Applications Kesong Liu,†,∥ Moyuan Cao,† Akira Fujishima, and Lei Jiang*,†,‡ †Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, PR China ‡Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China Research Institute for Science and Technology, Photocatalysis International Research Center, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan Institute for Superconducting and Electronic Materials, University of Wollongong, Innovation Campus, Squires Way, North Wollongong, NSW 2500, Australia

Fly-eye inspired superhydrophobic anti-fogging inorganic nanostructures

Fly-eye bio-inspired inorganic nanostructures are synthesized via a two-step self-assembly approach, which have low contact angle hysteresis and excellent anti-fogging properties, and are promising candidates for anti-freezing/fogging materials to be applied in extreme and hazardous environments.

Peanut leaf inspired multifunctional surfaces

Nature has long served as a source of inspiration for scientists and engineers to design and construct multifunctional artificial materials. The lotus and the peanut are two typical plants living in the aquatic and the arid (or semiarid) habitats, respectively, which have evolved different optimized solutions to survive. For the lotus leaf, an air layer is formed between its surface and water, exhibiting a discontinuous three-phase contact line, which resulted in the low adhesive superhydrophobic self-cleaning effect to avoid the leaf decomposition. In contrast to the lotus leaf, the peanut leaf shows high-adhesive superhydrophobicity, arising from the formation of the quasi-continuous and discontinuous three-phase contact line at the microscale and nanoscale, respectively, which provides a new avenue for the fabrication of high adhesive superhydrophobic materials. Further, this high adhesive and superhydrophobic peanut leaf is proved to be efficient in fog capture. Inspired by the peanut leaf, multifunctional surfaces with structural similarity to the natural peanut leaf are prepared, exhibiting simultaneous superhydrophobicity and high adhesion towards water.

Superhydrophobic metallic glass surface with superior mechanical stability and corrosion resistance

Superhydrophobic surface with mechanical stability and corrosion resistance is long expected due to its practical applications. We show that a micro-nano scale hierarchical structured Pd-based metallic glass surface with superhydrophobic effect can be prepared by the thermoplastic forming, which is a unique and facile synthesis strategy for metallic glasses. The superhydrophobic metallic glass surface without modification of low surface energy chemical layer also exhibits superior mechanical stability and corrosion resistance compared with conventional superhydrophobic materials. Our results indicate that the metallic glass is a promising candidate superhydrophobic material for applications.

Facile creation of bio-inspired superhydrophobic Ce-based metallic glass surfaces

A bio-inspired synthesis strategy was conducted to fabricate superhydrophobic Ce-based bulk metallic glass (BMG) surfaces with self-cleaning properties. Micro-nanoscale hierarchical structures were first constructed on BMG surfaces and then modified with the low surface energy coating. Surface structures, surface chemical compositions, and wettability were characterized by combining scanning electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, and contact angle measurements. Research indicated that both surface multiscale structures and the low surface free energy coating result in the final formation of superhydrophobicity.

Superhydrophobicity‐Mediated Electrochemical Reaction Along the Solid–Liquid–Gas Triphase Interface: Edge‐Growth of Gold Architectures

A superhydrophobic pillar-structured electrode leads to uncommon electrochemical behavior. The anti-wetting reaction surface restricts the contact between electrolyte and electrode to the pillar tops, as a result of trapped air pockets in the gaps between pillars. The electrochemical reaction occurs mainly at the solid/liquid/gas triphase interface, instead of the traditional solid/liquid diphase surface, yielding unique edge-growth structures - for example gold microflowers - on the top of each pillar.

Bio-inspired special wetting surfaces via self-assembly

Self-assembly is the fundamental principle, which can occur spontaneously in nature. Through billions of years of evolution, nature has learned what is optimal. The optimized biological solution provides some inspiration for scientists and engineers. In the past decade, under the multi-disciplinary collaboration, bio-inspired special wetting surfaces have attracted much attention for both fundamental research and practical applications. In this review, we focus on recent research progress in bio-inspired special wetting surfaces via self-assembly, such as low adhesive superhydrophobic surfaces, high adhesive superhydrophobic surfaces, superamphiphobic surfaces, and stimuli-responsive surfaces. The challenges and perspectives of this research field in the future are also briefly addressed.

A novel reusable superhydrophilic NiO/Ni mesh produced by a facile fabrication method for superior oil/water separation

There is a critical need to develop durable and reusable materials for oil–water separation, especially in harsh environments. Traditional anti-fouling mesh-based separation technologies are not reusable and limited by poor temperature resistance. Here we report a novel superhydrophilic and underwater superoleophobic NiO/Ni mesh which shows superior oil/water separation in harsh environments, with reusable and durable properties that can separate different oil–water mixtures with and without sand and soil contaminants, a >99% separation efficiency and up to 5.4 × 104 L m−2 h−1 permeate flux. The material is able to retain its superior performance over the 20 cycles we measured and for mixtures of sticky oils its performance is easily recoverable after a quick heat treatment. Our separation methodology is solely gravity-driven and consequently is expected to be highly energy-efficient. We anticipate that our separation methodology will have numerous applications, including in the clean-up of oil spills, wastewater treatment and other harsh condition oil–water separations.