Biomimetic research indicates that many phenomena regarding wettability in nature, such as the self-cleaning effect on a lotus leaf and cicada wing, the anisotropic dewetting behavior on a rice leaf, and striking superhydrophobic force provided by a water strider's leg, are all related to the unique micro- and nanostructures on the surfaces. It gives us much inspiration to realize special wettability on functional surfaces through the cooperation between the chemical composition and the surface micro- and nanostructures, which may bring great advantages in a wide variety of applications in daily life, industry, and agriculture. This Account reviews recent progress in these aspects.

From soaking wet to bone dry: The concept of reversible switching between superhydrophilicity and superhydrophobicity of a surface (see picture) exploits the thermally responsive wettability of poly(N‐isopropylacrylamide), and this property is enhanced by surface roughness.

room temperature. The products were examined using an X-ray diffractometer (RINT 2200HF) and a scanning electron microscope (JSM -6700F). The products were dispersed onto copper grids with an amorphous carbon film and further characterized structurally and chemically by using a high-resolution transmission electron microscope (JEM-3000F) fitted with an X-ray energy dispersive spectrometer. The photoluminescence spectra were recorded at room temperature using a He±Cd laser as an excitation source at a wavelength of 325 nm.

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A fundamental and persistent problem in the study of carbonbased electrode materials for lithium ion batteries is the question of how many lithium ions can be inserted onto a C 6 aromatic ring. Although different empirical models of Li x /C 6 (x < 3) have been proposed, the question remains unresolved. Herein we employ 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), an aromatic compound containing a naphthalene ring system (fused C 6 aromatic rings), to demonstrate that each carbon in a C 6 ring can accept a Li ion to form a Li 6 /C 6 additive complex through a reversible electrochemical lithium addition reaction. This process results in Li ion insertion capacities of up to nearly 2000 mA h g À1 , depending on the exact molecular structure. This value is several times higher than any other organic electrode material previously reported and can be fully released under certain conditions. Our experiments and theoretical calculations indicate that the anhydride groups on the sides of the aromatic system are crucial for this process, which provides a promising strategy for the design of novel high-performance organic electrode materials.Organic molecules [1] are intriguing candidates for electrode materials for use in rechargeable Li ion batteries. [2][3][4] The application of such species has aroused much interest recently, owing to the obvious advantages of such a system: no need for rare metals, low safety risks compared to transition metal oxides, and design flexibility at the molecular level. [5][6][7][8] However, organic molecules are usually considered to possess relatively poor specific energies and cycling properties, as compared to those of inorganic materials, and these factors greatly limit their practical application. Recently, studies on aromatic carbonyl derivatives [9,10] showed that organic materials can possess outstanding electrochemical performance comparable to, or even superior to, inorganic materials. [9,11,12] Furthermore, the wide diversity of organic redox systems, [1] as well as the excellent flexibility in their molecular design, suggest even greater prospects for these materials, and this has inspired the exploration of new organic Li ion insertion systems with improved performance.Aromatic C 6 rings are the basic structural units of graphite and other carbon-based electrode materials, which are the most commonly used anodes in commercial Li ion batteries owing to their high electric conductivity and low cost. [13][14][15] It has traditionally been believed that each C 6 ring can accept one Li ion to form an intercalated Li/C 6 complex, giving a relatively low theoretical capacity of 372 mA h g À1 . Recently, studies on graphene, [16][17][18] nanographene, [19,20] and their derivatives reveal that, through the reduction of size and dimensionality, these materials exhibit unique electric and electrochemical properties superior to those of conventional graphitic materials; thus, these materials are currently a hot research topic. In studies of electrode materials for Li ion batterie...

In general, superhydrophobic surfaces [1,2] with a water contact angle (CA) greater than 150°can be obtained by controlling the topography of hydrophobic surfaces, while superhydrophilic surfaces with a CA of about 0°can be realized through a three-dimensional (3D) [3] or two-dimensional (2D) capillary effect [4] on hydrophilic surfaces. The surface roughness dramatically enhances the CA on the hydrophobic surface but decreases the CA on the hydrophilic surface owing to the capillary effect, which is consistent with Wenzel's equation. [5] The fundamental mechanism of these phenomenaproposes that a combination of a hierarchical micro/nanostructure is essential for superhydrophilicity/superhydrophobicity. Recently, with the development of the combination of responsive materials and surface roughness, [6,7] several thermally, pH, or optically responsive smart interfacial materials that can switch between superhydrophilicity and superhydrophobicity have been reported: for example, a temperature-responsive polymer poly(N-isopropyl acrylamide (PNIPAAm); [6] photoresponsive materials, such as ZnO, [8] spiropyram, [8] two-level-structured self-adaptive surfaces, [9] the photoswitched wettability on an electrostatic self-assembled monolayer; [8] and a reversible pH-responsive surface. [10] However, all of these surfaces [11,12] are responsive to only one kind of external stimuli, such as temperature, [6] light, [8] or pH. [10] To the best of our knowledge, a dual-responsive surface that switches between hydrophilic and hydrophobic has never been reported, to say nothing of a dual-responsive surface that switches between superhydrophilic and superhydrophobic.In this communication, a dual-stimuli-responsive surface with tunable wettability, reversible switching between superhydrophilicity and superhydrophobicity, and responsivity to both temperature (T) and pH, is reported. Such surfaces are obtained by simply fabricating a poly(N-isopropyl acrylamide-co-acrylic acid) [P(NIPAAm-co-AAc)] copolymer thin film on both a flat and a roughly etched silicon substrate. Reversible switching between superhydrophilicity and superhydrophobicity can be realized over both a narrow temperature range of about 10°C and over a relatively wide pH range of about 10. This dual-responsive property is a result of the combined effect of the chemical variation of the surface and the surface roughness. In contrast to the roughness-enhanced homo-PNIPAAm film that is only responsive to temperature, the dual responsivity of the P(NIPAAm-co-AAc) films is due to the effective addition of the pH-sensitive component, acrylic acid (AAc). In addition, the lower critical solubility temperature (LCST) of the copolymer is tunable with increasing pH.The copolymer P(NIPAAm-co-AAc) thin films are fabricated on both a flat and a rough silicon substrate by a typical surface-initiated atom transfer radical polymerization. [13] Compared with Figure 1a (left), which shows the flat substrate, Figure 1a (right) shows a typical scanning electron microscopy ...

Chiral phenomena are ubiquitous in nature from macroscopic to microscopic, including the high chirality preference of small biomolecules, special steric conformations of biomacromolecules induced by it, as well as chirality-triggered biological and physiological processes. The introduction of chirality into the study of interface interactions between materials and biological systems leads to the generation of chiral biointerface materials, which provides a new platform for understanding the chiral phenomena in biological system, as well as the development of novel biomaterials and devices. This critical review gives a brief introduction to the recent advances in this field. We start from the fabrication of chiral biointerface materials, and further investigate the stereo-selective interaction between biological systems and chiral interface materials to find out key factors governing the performance of such materials in given conditions, then introduce some special functionalities and potential applications of chiral biointerface materials, and finally present our own thinking about the future development of this area (108 references).

Insufficient ionic conductivity and freezing of the electrolyte are considered the main problems for electrochemical energy storage at low temperatures (low T). Here, an electrolyte with a freezing point lower than −130 °C is developed by using dimethyl sulfoxide (DMSO) as an additive with molar fraction of 0.3 to an aqueous solution of 2 m NaClO4 (2M‐0.3 electrolyte). The 2M‐0.3 electrolyte exhibits sufficient ionic conductivity of 0.11 mS cm−1 at −50 °C. The combination of spectroscopic investigations and molecular dynamics (MD) simulations reveal that hydrogen bonds are stably formed between DMSO and water molecules, facilitating the operation of the electrolyte at ultra‐low T. Using DMSO as the electrolyte additive, the aqueous rechargeable alkali‐ion batteries (AABs) can work well even at −50 °C. This work provides a simple and effective strategy to develop low T AABs.