Lanlan Wang

Magnetic Driving Flowerlike Soft Platform: Biomimetic Fabrication and External Regulation.

Nature-inspired actuators that can be driven by various stimuli are an emerging application in mobile microrobotics and microfluidics. In this study, a soft and multiple-environment-adaptive robotic platform with ferromagnetic particles impregnated in silicon-based polymer is adopted to fabricate microrobots for minimally invasive locomotion and control interaction with their environment. As an intelligent structure of platform, the change of its bending, deformation, and flapping displacement is rapid, reversible, and continuously controllable with sweeping and multicycle magnetic actuation. The bending angle of the soft platform (0.2 mm in thickness and 8.5 mm in length) can be deflected up to almost 90° within 2.7 s. Experiments demonstrated that the flexible platform of human skin-like material in various shapes, that is, flowerlike shapes, can transport a cargo to targeted area in air and a variety of liquids. It indicates excellent magnetic-actuation ability and good controllability. The results may be helpful in developing a magnetic-driven carrying platform, which can be operated like a human finger to manipulate biological objects such as single cells, microbeads, or embryos. Especially, it is likely to be used in harsh chemical and physical circumstances.

Bio-inspired directional high-aspect-ratio nanopillars: fabrication and actuation

The Dynamic nature and responsive behaviour are the most attractive features of biological structures, and comprise the goals for next-generation smart materials. The nanostructured arrays provide unique topographic patterns that confer wetting, optical, and many other functions, but their actuation at the sub-micrometer scale is still a challenging goal. In this paper, we provide a simple route to fabricate ordered arrays of slender nanopillars with submicron diameters (400–500 nm) and high aspect ratios (20–40), with controllable slanted angles (60–90°). Experiments reveal that the fabricated slender nanopillars are flexible so that their orientation can be dynamically manipulated in response to an external electric field, while the stiffness can prevent ground or lateral collapse. The high aspect ratio nanopillars with orientation tunability can find applications in the development of smart materials, gecko-inspired reversible adhesion, etc.

Bio-inspired eyes with eyeball-shaped lenses actuated by electro-hydrodynamic forces

Inspired by vertebrate eyes, electro-hydrodynamic forces functioning as the ciliary muscle of bio-inspired eyes are extremely appealing in micro-optical devices. Eyeball-shaped lenses, composed of a liquid-core-cladding microlens array (LCC-MLA) is firstly utilized to fabricate a bio-inspired eye array through electro-hydrodynamic actuation. In this work, when the applied voltage increases, the microlens shape evolves from spherical crown to LCC-MLA shape (prolate egg). When the applied voltage is removed, the microlens shape changes from prolate egg to sphere. At a result, the electro-hydrodynamic force difference upon the lens interface leads to the adjustment of lens curvature. In addition, bio-inspired eyes manifest reversible 6-fold zoom and a fast responding time (∼50 ms). In contrast with a traditional tunable lens, the LCC-MLA is closer to a biological shape with wide vari-focal ability by electro-hydrodynamic actuation. Herein, these excellent properties make LCC-MLA promising for optics-based imaging sensors.

The bottom-up chemical growth of ZnO NRs on patterned IDEs and its potential application as micro-structured sensors

ZnO nanorods (NRs) micro-structured Sensors utilizing integration of ZnO NRs on microscale interdigitated electrodes (μIDEs) was fabricated and characterized. The ZnO NRs has been grown by simple CBD method directly on the IDEs which were formed on glass substrates by conventional photolithography and magnetron sputtering techniques. The average diameter of the ZnO NRs can be about 40-100 nm, and the length can be varied from 1 to 8 μm by changing growth systems and controlling growth time. When gas targets, such as ethanol, bind onto the ZnO NRs, the conductance between IDEs will change. Clear responses were obtained by measuring and comparing current-voltage (I-V) characteristic of the sensor before and after adsorbing gases.

Zinc oxide nano-chrysanthemum as field-emission cathode synthesized on n-doped silicon microstructures

Summary form only given. ZnO Nano-chrysanthemum arrays are both synthesized on silicon nano-needles and in silicon micro-holes with hydrothermal method. A ZnO Nano-chrysanthemum is a bunch of ZnO nanorods reaches out from one root. The influence of the reaction time has been carefully discussed and the Van der Waals force is regarded as the driving force from one needle to one Nano-chrysanthemum. This configuration helps suppressing the field screen-effect at a relatively high emission tip density. The influence of the reaction time and the concentration of hydrothermal solution on morphology have been carefully discussed. Turn-on fields as low as 3.35 V/μm and 5.25V/μm from ZnO nano-chrysanthemum on silicon nano-needles and in silicon micro-holes are reported, respectively. A field enhancement factor of 5523 is estimated for ZnO nano-chrysanthemum on silicon nano-needles.