Artifi cial superhydrophobic surfaces [1][2][3][4][5][6][7][8][9][10] with water contact angles (CAs) greater than 150 ° have been intensively investigated due to their unique "anti-water" property that could be utilized in a wide range of applications. [11][12][13] Recent development of intelligent devices, such as microfl uidic switches and biomedicine transporters, makes strong demands on surface wettability control, therefore, responsive surfaces have become a signifi cant issue for superhydrophobic studies. Up to now, various smart surfaces have been successfully developed as reversible switches for wettability control through a micronanostructured surface on a responsive material. [14][15][16][17][18][19][20][21][22][23][24][25] These unique tunings of surface wettability greatly contributed to refi ned control of surface wettability. With the thorough understanding of superhydrophobic phenomenon, superhydrophobic surfaces have been classifi ed into fi ve states [ 26 ] according to the details of CA hysteresis, which have been well verifi ed on different samples based on experimental results. [ 1 , 8 , 27-29 ] Superhydrophobic surfaces in different states show distinctive advantages in varied applications. Hence, efforts have also been devoted to precise tuning between different superhydrophobic states. For example, Lai et al. [ 23 a] investigated superhydrophobic surfaces with controlled adhesion to water droplets by using different kinds of rough surfaces. Li et al. [ 23 b] observed reversible switching between a transitional state (sliding angle of 75 ° ) and the Wenzel superhydrophobic state (high adhesion force) by changing the temperature. This inspired no-loss microdroplet transfer and trace-liquid reactor applications, [ 15 ] which usually need precise control of water droplet movement on the same surface from "roll-down" to "pinned" superhydrophobic states. Nevertheless, this no-loss transfer of a given water droplet requires a sensitive in situ tuning of surface wettability. Jiang et al. have reported an in situ control of magnetic droplet movement using extra magnetic fi eld, where the tuning was based not on pure water droplets, but on magnetic liquids. [ 27 ] From the practical point of view, it is still worth pointing out that the above-mentioned tuning approaches usually depend on harsh tuning conditions, such as UV irradiation, [ 18 ] electrical current, [ 19 , 21 ] a wide range of temperature, [ 23 ] or treatments by chemical solvents. [ 22 , 25 ] They may be not suitable for mild condition applications. For example, enzymes or biological cells in microfl uidic devices would be seriously affected under UV irradiation, temperature change, or addition of chemical substances. In addition, most of these tunable surfaces are based on artifi cially introduced material compositions or particular material species, [18][19][20][21][22][23][24][25] such as azobenzene and metal oxides, which suffer from poor biocompatibility. Therefore, it is urgently desirable to fi nd a simple, environmentally...

Closed-packed high numerical aperture (NA) microlens arrays (MLA) are highly desirable for high resolution imaging and high signal-to-noise-ratio detection in micro-optical and integrated optical applications. However, realization of such devices remains technically challenging. Here, we report high quality fabrication of curved surfaces and MLAs by taking the full advantage of surface self-smoothing effect by creating highly reproducible voxels and by adopting an equal-arc scanning strategy. MLA of approximately 100% fill ratio and NA of 0.46, much greater than those ever reported, 0.13, is demonstrated, whose excellent optical performance was approved by the sharp focusing and high resolution imaging.

In recent years, metal nanowiring for circuitry and electronic interconnection has attracted much attention due to the growing requirements of highly integrated microcircuits, and is of benefit to the miniaturization of device features. [1] Generally, ultraviolet photolithography, which was considered a typical processing route for metal wiring, has already greatly contributed to integrated circuits. [2] However, the lithographic route shows strong demands on the surface flatness of each layer in the multilevel chip architectures. To meet the processing nature of lithography, a global planarization of interlayer metals by chemical-mechanical polishing is therefore needed to reduce the interval between the metal layer and the photomask, and to guarantee exposure resolution when wires reach the sub-300 nm scale. Two-photon absorption (TPA) has also been tried for the fabrication of metal microstructures by using suitable salt solutions as the metal source and photosensitive molecules as the photoinitiator. [3][4][5] However, these studies aimed at refined planar periodic gratings or dot arrays [6] for plasmonic wave coupling or three-dimensional (3D) mold making, which more or less ignore the conductivity of these precise metal structures. For example, by using surfactants as particle-growth inhibitor, delicate 3D structures with a smooth surface were achieved, [7] whereas the conductivity of these metal microstructures was significantly debased due to the residual organic components.To the best of our knowledge, both the photolithography and TPA micro/nanoprocessing conducted so far have focused on fabrication on flat substrates. [8][9][10] These methods cannot meet the increasing demands of circuitry and electronic connections on nonplanar substrates in microelectromechanical systems (MEMS), [1] lab on a chip (LoC), [11] and other intelligent microsystems. Taking LoC as an example, if an appropriate microheater could be embedded on the immediate base inside a microfluidic channel instead of sitting several hundreds of micrometers apart on the rear of the substrate, as is usually done with Peltier thermoelectric elements, [12] integrated resistive heaters, [13][14][15][16][17] and Joule heating of ionic liquids, [18] then local temperature regulation of fluids with higher precision, quicker response, and smarter switching at the exact point of care may be realized due to the effectively reduced thermal inertia. Such a capability is particularly desired for temperature regulation of miniaturized LoC systems that involve repeated thermal cycling, such as DNA amplification by the polymerase chain reaction (PCR), which comprises three sequential steps of denaturation (95 8C), annealing (55 8C), and extension (72 8C). [12] Nevertheless, convenient introduction of a local heating circuit inside a ready channel is almost inaccessible for lithography and other currently available micro/nanofabrication methods. Therefore, there is an urgent need for flexible micro/nanoprocessing technologies for metal nanowiring on nonplan...