Browsing by Author "Chen, Hui-Jiuan"

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Electrically robust silver nanowire patterns transferrable onto various substrates
(2016)
Liu, Gui-Shi
;
Liu, Chuan
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Chen, Hui-Jiuan
;
Cao, Wu
;
Qiu, Jing-Shen
We report a facile technique for patterning and transferring silver nanowires (AgNWs) onto various substrates. By employing only UV/O-3 and vapor treatment of hexamethyldisilazane (HMDS), we are able to accurately manipulate the surface energy via alternating the terminal groups of a polydimethylsiloxane (PDMS) substrate, so as to assist selective formation and exfoliation of AgNW films. A simple UV/O-3 treatment on PDMS enables uniform, well-defined, and highly conductive patterns of AgNWs after spin-coating. A vapor treatment of HMDS lowers the surface energy of the oxidized PDMS so that the patterned AgNWs embedded in an epoxy resin (EPR) are cleanly transferred from the PDMS to the target substrate. It is found that the AgNW-EPR composite on polyethylene glycol terephthalate (PET) exhibits remarkable durability under the bending test, tape test, ultrasonic treatment in water, and immersion of chemical solvents. In addition, we demonstrate that the AgNW-EPR composite work well as conductive patterns on the oxidized PDMS, polyvinyl alcohol (PVA), paper, and curved glass. The facile technique extends the applicability of AgNWs in the field of electronics, and it is potentially applicable to other nanomaterials.
Enhancement of Electroactive Phases of PVDF by Mixing SiC Nanowires for Pressure Sensing
(2016)
Huang, Jiefang
;
Han, Songjia
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Chen, Hui-Jiuan
;
Luo, Zhenhua
;
Shieh, Han-Ping D.
Poly(vinylidene fluoride) (PVDF) is one of the ideal materials for wearable pressure sensing owing to its excellent piezoelectric property, good flexibility, and easy fabrication processing. In this work, we mixed PVDF matrix with silicon carbide (SiC) nanowires acting as an efficient nucleating agent to transform the non-polar a phase to polar beta and gamma phases to improve the crystallinity of electroactive phases and enhance the piezoelectricity of PVDF thin film.
Enhancement of Polar Phases in PVDF by Forming PVDF/SiC Nanowire Composite
(2016-12)
Huang, Jie-Fang
;
Han, Song-Jia
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Chen, Hui-Jiuan
;
Liu, Gui-Shi
;
Li, Gong-Tan
Different contents of silicon carbide (SiC) nanowires were mixed with Poly(vinylidene fluoride) (PVDF) to facilitate the polar phase crystallization. It was shown that the annealing temperature and SiC content affected on the phase and crystalline structures of PVDF/SiC samples. Furthermore, the addition of SiC nanowire enhanced the transformation of non -polar a phase to polar phases and increased the relative fraction of 13 phase in PVDF. Due to the nucleating agent mechanism of SiC nanowires, the ion dipole interaction between the negatively charged surface of SiC nanowires and the positive CH2 groups in PVDF facilitated the formation of polar phases in PVDF.
Enhancement of Polar Phases in PVDF by Forming PVDF/SiC Nanowire Composite
(2016-12)
Huang, Jie-Fang
;
Han, Song-Jia
;
Chen, Hui-Jiuan
;
Liu, Gui-Shi
;
Li, Gong-Tan
Different contents of silicon carbide (SiC) nanowires were mixed with Poly(vinylidene fluoride) (PVDF) to facilitate the polar phase crystallization. It was shown that the annealing temperature and SiC content affected on the phase and crystalline structures of PVDF/SiC samples. Furthermore, the addition of SiC nanowire enhanced the transformation of non -polar a phase to polar phases and increased the relative fraction of 13 phase in PVDF. Due to the nucleating agent mechanism of SiC nanowires, the ion dipole interaction between the negatively charged surface of SiC nanowires and the positive CH2 groups in PVDF facilitated the formation of polar phases in PVDF.
Hybrid Effect of Crossed Alignment and Multi-Stacking Structure on the Percolation Behavior of Silver Nanowire Networks
(2015-07-01)
Yang, Bo-Ru
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Liu, Gui-Shi
;
Han, Song-Jia
;
Cao, Wu
;
Chen, Hui-Jiuan
Owing to the superiority of being flexible, highly conductive, and extremely transparent, silver nanowire (AgNW) has been regarded as a possible candidate to replace indium-tin-oxide (ITO) for flexible transparent conductive films (TCFs), flexible electronics, and flexible display applications. To make TCFs with lower sheet resistance (R-s), but without sacrificing the optical transmittance, the deployment of AgNWs is very critical. A crossed-alignment method along with multi-stacking structure was proposed to lower the percolative threshold, which thus can decrease the R-s by a factor of more than two, in the premise of not affecting the optical transmittance.
Microchannel Wetting for Controllable Patterning and Alignment of Silver Nanowire with High Resolution
(2015-09-30)
Yang, Bo-Ru
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Cao, Wu
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Liu, Gui-Shi
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Chen, Hui-Jiuan
;
Noh, Yong-Young
Patterning and alignment of conductive nanowires are essential for good electrical isolation and high conductivity in various applications. Herein a facile bottom-up, additive technique is developed to pattern and align silver nanowires (AgNWs) by manipulating wetting of dispersions in microchannels. By forming hydrophobic/hydrophilic micropatterns down to 8 mu m with fiuoropolymer (Cytop) and SiO2, the aqueous AgNW dispersions with the optimized surface tension and viscosity self-assemble into microdroplets and then dry to form anisotropic AgNW networks. The alignment degree characterized by the full width at half-maximum (FWHM) can be well-controlled from 39.8 degrees to 84.1 degrees by changing the width of microchannels. A mechanism is proposed and validated by statistical analysis on AgNW alignment, and a static model is proposed to guide the patterning of general NWs. The alignment reduced well the electrical resistivity of AgNW networks by a factor of 5 because of the formation of efficient percolation path for carrier conduction.
TiO2 nanowire-templated hierarchical nanowire network as water-repelling coating
(2017-11-01)
Hang, Tian
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Chen, Hui-Jiuan
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Xiao, Shuai
;
Yang, Chengduan
;
Chen, Meiwan
Extraordinary water-repelling properties of superhydrophobic surfaces make them novel candidates for a great variety of potential applications. A general approach to achieve superhydrophobicity requires low-energy coating on the surface and roughness on nano-and micrometre scale. However, typical construction of superhydrophobic surfaces with micro-nano structure through top-down fabrication is restricted by sophisticated fabrication techniques and limited choices of substrate materials. Micro-nanoscale topographies templated by conventional microparticles through surface coating may produce large variations in roughness and uncontrollable defects, resulting in poorly controlled surface morphology and wettability. In this work, micro-nanoscale hierarchical nanowire network was fabricated to construct self-cleaning coating using one-dimensional TiO2 nanowires as microscale templates. Hierarchical structure with homogeneous morphology was achieved by branching ZnO nanowires on the TiO2 nanowire backbones through hydrothermal reaction. The hierarchical nanowire network displayed homogeneous micro/nano-topography, in contrast to hierarchical structure templated by traditional microparticles. This hierarchical nanowire network film exhibited high repellency to both water and cell culture medium after functionalization with fluorinated organic molecules. The hierarchical structure templated by TiO2 nanowire coating significantly increased the surface superhydrophobicity compared to vertical ZnO nanowires with nanotopography alone. Our results demonstrated a promising strategy of using nanowires as microscale templates for the rational design of hierarchical coatings with desired superhydrophobicity that can also be applied to various substrate materials.