Wearable electronic devices such as mobile communication devices, portable computers, and various sensors are the latest significant innovations in technology which use the Internet of Things (IoT) to track personal data. Wearable energy harvesters are required to supply electricity to such devices for the convenience of users. In this study, a textile-type triboelectric nanogenerator (T-TENG), produced using commercial electrode fibers, was fabricated to generate electrical energy using external mechanical stimulation. The commercial fiber was an electrode coated with Teflon on a copper wire with a diameter of ~ 320 μm. Using this commercial fiber, a T-TENG was easily fabricated by knitting and weaving. The performance of the T-TENG was analyzed to understand the effect of force and frequency. It was observed that the performance of the T-TENG did not degrade even under harsh conditions and treatment. The textile-type TENG possessed an energy harvesting capability with an output power density of ~ 0.36 W/m2 and could operate electronic devices by charging a capacitor.

Poly(dimethylsiloxane) (PDMS) is used in microfluidics owing to its biocompatibility and simple fabrication. However, its intrinsic hydrophobicity and biofouling inhibit its microfluidic applications. Conformal hydrogel-skin coating for PDMS microchannels, involving the microstamping transfer of the masking layer, is reported herein. A selective uniform hydrogel layer with a thickness of ∼1 μm was coated in diverse PDMS microchannels with a resolution of ∼3 μm, maintaining its structure and hydrophilicity after 180 days (6 months). The wettability transition of PDMS was demonstrated through the switched emulsification in a flow-focusing device (water-in-oil [pristine PDMS] to oil-in-water [hydrophilic PDMS]). A one-step beadbased immunoassay was performed to detect the anti-severe acute respiratory syndrome coronavirus 2 IgG using a hydrogel-skin-coated point-of-care platform.

Droplet and bubble manipulation in air and underwater, respectively, are of interest because of their potential applications in various areas related to microfluidics, gas collection, and other industrial applications. However, the fabrication of manipulation platforms capable of performing various functions (merging and mixing) and directionally moving droplets/bubbles on a single platform has rarely been reported. This paper describes a multifunctional manipulation platform designed using a slippery organogel channel capable of manipulating droplets and bubbles. The manipulation block can be fabricated by forming a polydimethylsiloxane channel using a 3D‐printed mold generated by a commercial 3D printer and filling it with a slippery organogel precursor. The fabricated manipulation platform can move various droplets regardless of viscosity, surface tension, acidity, or basicity; has a merging function; and can enhance mixing. As a functional block application, polyvinyl alcohol‐boric acid hydrogel is synthesized on a slippery organogel channel. Moreover, because of the nature of block assembly, new manipulation platforms that can perform desired functions can be created by assembling blocks. The proposed functional manipulation platform overcomes existing limitations and would have practical applications.