Jia Yao

Jilin University, Yung-chi, Jilin Sheng, China

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Publications (8)38.82 Total impact

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    ABSTRACT: A π-conjugated polymer containing an azobenzene segment in its backbone is found to be highly photo-responsive. As the polymer film is irradiated with an interfering laser beam, the trans-to cis- photo-isomerization in the polymer chain induces a great change to the chain configuration from a rigid-rod to an irregular coil, and a corresponding great local stress, which drives the chain transfer to form high contrast surface patterning.
    Polym. Chem. 10/2013; 4(21).
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    ABSTRACT: A simple strategy to realize new controllable 3D microstructures and a novel method to reversibly trapping and releasing microparticles are reported. This technique controls the height, shape, width, and arrangement of pillar arrays and realizes a series of special microstructures from 2-pillar-cell to 12 cell arrays, S-shape, chain-shape and triangle 3-cell arrays by a combined top down/bottom up method: laser interference lithography and capillary force-induced assembly. Due to the inherent features of this method, the whole time is less than 3 min and the fabricated area determined by the size of the laser beam can reach as much as 1 cm(2) , which shows this method is very simple, rapid, and high-throughput. It is further demonstrated that the 'mechanical hand'-like 4-cell arrays could be used to selectively trap/release microparticles with different sizes, e.g., 1.5, 2, or 3.5 μm, which are controlled by the period of the microstructures from 2.5 to 4 μm, and 6 μm. Finally, the 'mechanical hand'-like 4-cell arrays are integrated into 100 μm-width microfluidic channels prepared by ultraviolet photolithography, which shows that this technique is compatible with conventional microfabrication methods for on-chip applications.
    Small 11/2012; · 7.82 Impact Factor
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    ABSTRACT: In this Letter, an electro-optical probe configuration with polar molecule liquids as the sensing film is proposed to improve the voltage sensitivity. This method exhibited increases in intrinsic sensitivities better than 0.1 mV/√Hz, 2 orders of magnitude larger than the normal method using a GaAs probe in the same measurement system. Based on the mechanism of orientation polarization, the electro-optic coefficient was measured to be 250 pm/V by the Teng-Man method at a modulation field of 100 Hz. This technology will be promising in applications of low-frequency field detection.
    Optics Letters 04/2011; 36(7):1158-60. · 3.39 Impact Factor
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    ABSTRACT: In this letter, we report a kind of smart surfaces with reversible switching between isotropy and anisotropic wetting, which was realized by one-direction curvature tuning on flexible superhydrophobic surfaces. Along the curvature change, the wettability of this flexible film was changed from isotropic state (150°/150°) into anisotropic state confirmed by its anisotropic contact angles (150°/160°) and sliding properties (30°/65°). Further investigation revealed that the surface wettability was changed from composited pinned state into transitional state. This was attributed to the increase in roughness factor and the decrease in the contact area between the water droplet and the pillar array. At last, we demonstrate that the wetting states between isotropy and anisotropy on this flexible superhydrophobic film could be reversibly switched by curvature for many times (>10).
    Applied Physics Letters 02/2011; 98(8):081902-081902-3. · 3.52 Impact Factor
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    Advanced Materials 01/2011; 23(4):545-9. · 14.83 Impact Factor
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    ABSTRACT: In this paper, one simple method to control two-direction anisotropic wetting by regular micropearl arrays was demonstrated. Various micropearl arrays with large area were rapidly fabricated by a kind of improved laser interference lithography. Specially, we found that the parallel contact angle (CA) theta(2) decreased from 93 degrees to 67 degrees as the intensity ratio of four laser beams increased from 2:1 to 30:1, while the perpendicular CA theta(1) determined by the thickness of the resin remained constant. This was interpreted as the decrease of height variations Delta h from 1100 to 200 nm along the parallel direction caused by the increase of the intensity ratio. According to this rule, both theta(1) and theta(2) could be simultaneously controlled by adjusting the height variation Delta h and the resin thickness. Moreover, by combining appropriate design and low surface energy modification, a natural anisotropic rice leaf exhibiting CAs of 146 degrees +/- 2 degrees/153 degrees +/- 3 degrees could be mimicked by our anisotropic biosurface with the CAs 145 degrees +/- 1 degrees/150 degrees +/- 2 degrees. We believe that these controlled anisotropic biosurfaces will be helpful for designing smart, fluid-controllable interfaces that may be applied in novel microfluidic devices, evaporation-driven micro/nanostructures, and liquid microdroplet directional transfer.
    Langmuir 07/2010; 26(14):12012-6. · 4.38 Impact Factor
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    ABSTRACT: The study of anisotropic wetting has become one of the most important research areas in biomimicry. However, realization of controlled anisotropic surfaces remains challenging. Here we investigated anisotropic wetting on grooves with different linewidth, period, and height fabricated by laser interference lithography and found that the anisotropy strongly depended on the height. The anisotropy significantly increased from 9° to 48° when the height was changed from 100 nm to 1.3 μ m . This was interpreted by a thermodynamic model as a consequence of the increase of free energy barriers versus the height increase. According to the relationship, controlled anisotropic surfaces were rapidly realized by adjusting the grooves’ height that was simply accomplished by changing the resin thickness. Finally, the perpendicular contact angle was further enhanced to 131°±2° by surface modification, which was very close to 135°±3° of a common grass leaf.
    Applied Physics Letters 03/2010; · 3.52 Impact Factor
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    ABSTRACT: In nature, rice leaves exhibit special anisotropic sliding capabilities. Although researchers have succeeded in fabricating artificial rice leaf structures and realizing the wettability function of the leaf surface, these methods used to date are complex and do not allow the fabrication of surfaces with large area. Herein, we adopted a simple technology - two steps soft transfer to fabricate biomimetic rice leaf. The fabricated surface well reproduced the structures of the rice leaf surface and exhibited a static superhydrophobic property similar to that of the real rice leaf surface. In terms of its dynamic wettability, it clearly exhibited an anisotropic sliding property. Systematic measurements showed that the sliding angles parallel and perpendicular with the vein direction were 25° and 40°, respectively. The method was simple and reliable, without the need for expensive instruments and complex technologies, which could be used for the rapid fabrication of large-area artificial rice leaf surfaces. We believe that the artificial rice leaf surface fabricated by this method has great potential applications in biomimetic functional surfaces, microfluidics, and so on.
    Chinese Science Bulletin 57(20). · 1.37 Impact Factor