| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Wednesday Sessions |
| Session TF-WeE |
| Session: | Emerging Topics: Growth and Properties of Electronic Materials, 2D Layers, and Metallic-glass Thin Films |
| Presenter: | Jinn P. Chu, National Taiwan University of Science and Technology, Taiwan, Republic of China |
| Correspondent: | Click to Email |
Thin film metallic glass (TFMG) is a new class of metallic thin film with unique characteristics, including high strength, high ductility, smooth surface, absence of grain boundaries, low coefficient of friction, and corrosion resistance, though their bulk forms are already well-known for properties such as because of their amorphous structure. Thin films prepared by vapor-to-solid deposition are expected to be further from equilibrium than those prepared by liquid-to-solid melting or casting processes. This is expected to further improve the glass forming ability and widen the composition range for amorphization. In this talk, we successfully fabricated the first-ever metallic glass nanotubes (MGNTs) on Si by a simple lithography and sputter deposition process for very large-scale integration. Like biological nanostructured surfaces, MGNTs show some surprising water repelling and attracting properties. Nanotubes are 500-750 nm tall and 500-750 nm in diameter [1]. The MGNT surface becomes hydrophobic and repels water. Upon heating and cooling the array, water can be repelled and attached to the surface [1]. Two examples will be presented in this talk based on modifications of this scheme. First, after modification of biotin, the array acts as a waveguiding layer for an optical sensor. The MGNT sensor waveguide could readily detect the streptavidin by monitoring the shift. With a detection time of 10 min, the detection limit for streptavidin is estimated to be 25 nM. Thus, the arrays may be used as a versatile platform for high-sensitive label-free optical biosensing [2]. Further, the array is prepared on a heating device on Si and, with an applied electric voltage to the heating device underneath, the MGNT surface was heated to generate an extending force from these nanochambers up to ~75°C in order for the array to be functioned as biomimetic artificial suckers for thermally adhesion response in biological systems [3]. As a result, the adhesive forces of the MGNT arrays can be as high as 11.2 N cm–2.
References
[1] J. K. Chen, W. T. Chen, C. C. Cheng, C. C. Yu and J. P. Chu, Metallic glass nanotube arrays: preparation and surface characterizations, Materials Today, 21 (2018), 178-185.
[2] W. T. Chen, S. S. Li, J. P. Chu, K. C. Feng, J. K. Chen, Fabrication of ordered metallic glass nanotube arrays for label-free biosensing with diffractive reflectance, Biosensors and Bioelectronics, 102 (2018), 129-135.
[3] W. T. Chen, K. Manivannan, C. C. Yu, J. P. Chu and J. K. Chen, Fabrication of an artificial nanosucker device with a large area nanotube array of metallic glass, Nanoscale, 10 (2018) 1366-1375.