Low-cost and simple fabrication of micro-mask/micro-channels on different substrates based on water-soluble fiber poly (vinyl alcohol) (PVA)

Here we report an approach to fabricate micro-mask/micro-channels using water-soluble fiber poly (vinyl alcohol) (PVA). The scheme is a simple, environmentally friendly, and low-cost technology, that can realize the preparation of micro-mask/micro-channels on different substrates. Scanning electron microscope (SEM) and optical microscope (OM) are used to observe surface morphology and measured fiber diameter. We showed that a variety of micro-mask/micro-channels can be easily controlled by changing the swelling temperature and time of the PVA fiber. The swelling temperature was varied from 25 degrees C to 50 degrees C, the diameter of the fiber increased by 9.5 mu m, and the diameter and volume swelling rates reached 59.38% and 154%, respectively. Meanwhile, with the increase in swelling time, the diameter and volume swelling rate showed the same increasing trend. Additionally, we used the PVA fiber as a micro-mask to prepare the micro-channel on the WSe2 surface and verified the feasibility of the PVA fiber to prepare micro-mask/micro-channels by testing the electrical properties of the WSe2 sample. Finally, we also verified the feasibility of the above methods to fabricate micro-mask/micro-channels on different substrates such as conductive fibers, PDMS, and WSe2/SiO2Si, and proposed to realize nano-scale patterning through direct electrospinning. Therefore, it is expected to be more widely promoted in the future.