Experimental Study on Pool Boiling on Hydrophilic Micro/Nanotextured Surfaces with Hydrophobic Patterns

Over the past decades, pool boiling on various wetting surfaces has been intensively investigated to enhance boiling heat transfer and critical heat flux. In this study, to enhance the two thermal performances simultaneously, we developed hydrophilic micro/nanotextured surfaces with hydrophobic patterns. Using a silicon substrate, well-arrayed microtextures and randomly arrayed nanotextures were fabricated hierarchically using micro/nanoelectromechanical system processes. The top of the microtextures was coated locally with hydrophobic characteristics using specific self-assembled monolayer coating methods. Based on experimental data, we postulate that the critical heat flux was enhanced by the capillary-induced flow between microtextures and that nanotextures with superhydrophilicity contribute to the delay of the critical heat flux by better wetting the dried area. Owing to the hydrophobicity at the top of the micropillars, the nucleate site density and boiling heat transfer increased.

Selective control of the contact and transport between droplet pairs by electrowetting-on-dielectric for droplet-array sandwiching technology

Methodological advances in on-chip technology enable high-throughput drug screening, such as droplet-array sandwiching technology. Droplet-array sandwiching technology involves upper and lower substrates with a droplet-array designed for a one-step process. This technology is, however, limited to batch manipulation of the droplet-array. Here, we propose a method for selective control of individual droplets, which allows different conditions for individual droplet pairs. Electrowetting-on-dielectric (EWOD) technology is introduced to control the height of the droplets so that the contact between droplet-pairs can be individually controlled. Circular patterns 4 mm in diameter composed of electrodes for EWOD and hydrophilic–hydrophobic patterns for droplet formation 4 μl in volume were developed. We demonstrate the selective control of the droplet height by EWOD for an applied voltage up to 160 V and selective control of the contact and transport of substances. Presented results will provide useful method for advanced drug screening, including cell-based screening.

Selective Control of the Contact and Transport between Droplet Pairs by Electrowetting-on-Dielectric for Droplet-Array Sandwiching Technology

On-chip technology continuously explores and provides novel methods for high-throughput drug screening, such as droplet-array sandwiching technology. Droplet-array sandwiching technology involves upper and lower substrates with a droplet-array designed for a one-step process for drug screening, including cell-based screening. This technology is, however, limited to batch manipulation of the droplet-array. This paper proposes selective control of individual droplets, which allows different conditions for individual droplet pairs. Electrowetting-on-dielectric (EWOD) technology is introduced to control the height of the droplets so that the contact between droplet-pairs can be individually controlled. Circular patterns 4 mm in diameter composed of electrodes for EWOD and hydrophilic-hydrophobic patterns for droplet formation 4 μl in volume were developed. This paper presents and examines the selective control of the droplet height by EWOD for an applied voltage up to 160 V, followed by successful results of selective control of the contact and transport of substances.

Copper-assisted growth of high-purity carbon nanofiber networks with controllably tunable wettabilities

High-purity carbon nanofiber networks were grown on surfaces of ceramic boats via Cu-assisted CVD. After peeling off and selective plasma treatment, the invisible hydrophobic patterns on both their obverse and reverse surfaces were obtained.

GAPIN: Grouped and Aligned Protein Interface Networks

SummaryGAPIN is a web-based application for structural interaction network analysis among any type of PDB molecules, regardless of whether their interfaces are between chain-chain or chain-ligand. A special emphasis is given to graph clustering, allowing users to scrutinize target contexts for ligand candidates. We show how GAPIN can be used to unveil underlying hydrophobic patterns on a set of peptidase-inhibitor complexes. In another experiment, we show there is a positive correlation between cluster sizes and the presence of druggable spots, indicating that the clustering may discriminate the higher complexity of these hot subnetworks.Availability and implementationGAPIN is freely available as an easy-to-use web interface at https://[email protected], [email protected] informationSupplementary data are available online.

Direct Writing of Hydrophobic Sol-Gel Patterns

ABSTRACTSolution-based fabrication methods have been widely used for depositing uniform functional coatings. These coatings can be utilized in a variety of applications such as optoelectronics, biomedical, and energy. However, such fabrication techniques are not appropriate for directly depositing patterned micro/nano-scale features, which are required in many contact-based applications such as in MEMS.In this work we propose the direct writing of hydrophobic silica-based sol-gel patterns with sustained functionality and their subsequent tribological characterization. Such an approach may be an advantageous alternative to current lithography-based methods due to the relative ease of processing and low material waste. This investigation involves the abrasive wear and frictional analysis of patterned fluorinated silica sol-gel coatings that are directly printed onto glass substrates with a robotically controlled pneumatic nozzle system. Such work sheds light on the tribological properties of lithography-free processed hydrophobic patterns for applications spanning from micromotors to biomedical fluidic devices.