Ying-Hung Chen, Xuan-Xu Liu, Ping-Yen Hsieh, Ju-Liang He, Feng Chia University, Taichung City, Taiwan
As global living standards continue to rise, market demand for textile and polymer products has expanded beyond basic functionality to include aesthetics, comfort, durability, and environmental sustainability. In response, dry vacuum deposition techniques, offering a wide range of decorative possibilities, are increasingly replacing traditional wet processing methods. Among these, high-power impulse magnetron sputtering (HiPIMS) stands out for its ability to produce dense, strongly adherent films at low substrate temperatures. In this study, an indium-tin (In-Sn) alloy was deposited onto thermoplastic polyurethane (TPU) substrates using HiPIMS, aiming to create a durable, metallic luster surface suitable for high-fashion textiles, wearable electronics, and decorative consumer goods. A systematic optimization of the HiPIMS deposition parameters was conducted to tailor the morphology, optical properties, and mechanical durability of the In-Sn coatings on TPU films.
Experimental results demonstrate that the TPU substrate tolerates deposition conditions at a peak current density of 60 A/cm². A semi-transparent metallic appearance is achieved within a 1-minute deposition time; with extended deposition, the coating transitions to a highly reflective metallic luster. Bendability tests reveal that the In-Sn coating maintains strong adhesion after 100,000 bending cycles, meeting durability requirements for commercial applications. Overall, this work presents a promising approach for the development of aesthetically appealing, flexible, and durable TPU-based materials with reduced environmental impact.