Superhydrophobic surfaces have been used in various fields of engineering due to their resistance to corrosion and fouling and their ability to control fluid movement. Traditionally, superhydrophobic surfaces are fabricated via chemical methods of changing the surface energy or mechanical methods of controlling the surface topology. Many of the conventional mechanical methods use a top-to-bottom scheme to control the surface topolopy. Here, we develop a novel fabrication method of superhydrophobic substrates using a bottom-to-top scheme via polymer OSTE, which is a prototyping polymer material developed for the fabrication of microchips due to its superior photocuring ability, mechanical properties, and surface modification ability. We fabricate a superhydrophobic substrate by OSTE–OSTE micro mushroom forest via a two-step lithography process. At first, we fabricate an OSTE pillar forest as the mushroom stems; then, we fabricate the mushroom heads via backside lithography with diffused UV light. Such topology and surface properties of OSTE render these structures superhydrophobic, with water droplets reaching a contact angle of 152.9 ± 0.2°, a sliding angle of 4.1°, and a contact angle hysteresis of less than 0.5°. These characteristics indicate the promising potential of this substrate for superhydrophobic applications.
This work presents a novel μPAD packaging method using thermal contraction tubes to create hollow channels, significantly enhancing capillary flow rates (up to 1328%) and enabling applications like glucose detection and viscosity measurement.
This work presents a novel microfabrication process that addresses the interference of thiol groups on off-stoichiometry thiolene (OSTE) surfaces with the curing of polydimethylsiloxane (PDMS) by integrating the high-performance polymer Parylene-C. The process utilizes a Parylene-C coating to encapsulate the active thiol groups on the OSTE surface, enabling precise replication of PDMS microstructures. Based on this method, PDMS micropillar arrays and microwell arrays were successfully fabricated and applied in passive plasma separation and polymorphic crystal formation, respectively. The experimental results demonstrate that the plasma-separation chip efficiently isolates plasma from whole-blood samples with varying hematocrit (HCT) levels, achieving a separation efficiency of up to 57.5%. Additionally, the microwell array chip exhibits excellent stability and controllability in the growth of salt and protein crystals. This study not only provides a new approach for microfabricating microfluidic chips, but also highlights its potential applications in biomedical diagnostics and materials science.
Paper-based microfluidic devices (μPADs) have attracted significant attention for point-of-care testing (POCT), environmental monitoring, and food safety due to their low cost, ease of use, and minimal instrument dependence. However, fabricating high-resolution and reproducible microchannels on paper remains challenging. Conventional methods such as wax printing, photolithography, and inkjet printing are limited by resolution or equipment cost. Here, we present a low-cost, high-resolution fabrication method for μPADs, termed wax soft lithography, which combines wax printing with soft lithography. Through this method, microchannels with a minimum width of 234 ± 62 μm were consistently produced, and complex patterns were successfully fabricated, demonstrating high precision and reproducibility. As a proof-of-concept demonstration of device functionality, the fabricated μPADs were used to detect glucose in spiked urine samples, showing a concentration-dependent colorimetric response. This method provides an effective route for rapid production of high-resolution μPADs in resource-limited settings. With further validation before practical applications, this method shows promise for future development in POCT.