Filament Hydrophobicity Switching
Filament Hydrophobicity Switching - Related Videos
07:56
Drawing and Hydrophobicity-patterning Long Polydimethylsiloxane Silicone Filaments
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Cited by 3 •
2019
Here, we present a protocol to produce long filaments of polydimethylsiloxane (PDMS) silicone by gravity-drawing through a furnace. Filaments are on the order of hundreds of micrometers in diameter and tens of centimeters in length and are hydrophobically patternable via an Arduino-controlled corona discharge system.
08:58
Filamentous Fungi
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2023
Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona Demonstrating Author: Bradley Schmitz Fungi are heterotrophic eukaryotic organisms, and with the exception of yeasts, are aerobic. They are abundant in surface soils and are important for their role in nutrient cycling and the decomposition of organic matter and organic contaminants. White rot fungi (phanerochaete chryosporium) for example, (Figure 1) are known to degrade aromatics. Figure 1. White rot on...
02:44
Gliding Motility in Phormidium lacuna Filaments
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2025
Source: Weber, N., et al., Natural Transformation, Protein Expression, and Cryoconservation of the Filamentous Cyanobacterium Phormidium lacuna. J. Vis. Exp. (2022)This video demonstrates the procedure to assess gliding motility in Phormidium lacuna by homogenizing filament cultures to create a uniform suspension, preparing a Petri plate assay setup over a microscope slide, and visualizing filament movement.
03:22
Calcium-Dependent Hydrophobic Interaction Chromatography: A Technique to Purify Calcium-Binding Proteins Based on Hydrophobic Interactions
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2025
In this video, we demonstrate the purification of calcium-binding protein from a dialyzed cell lysate through calcium-dependent hydrophobic interaction chromatography. The calcium-binding proteins expose a hydrophobic region upon binding with calcium, facilitating interaction with a hydrophobic group on resin. Later these proteins are eluted using calcium chelator EDTA that reverses the interaction.
01:22
Switching of BJT
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2024
Switching behavior in Bipolar Junction Transistors (BJTs) is a fundamental aspect utilized in various electronic circuits, particularly for digital logic applications like switches and amplifiers. In a typical switching circuit, a BJT alternates between cut-off and saturation modes, corresponding to the "off" and "on" states, respectively, thus behaving like an ideal switch. Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are reverse-biased. The...
FAQs
Two engineering levers are central: surface chemistry and surface texture. Chemical changes alter how the filament interacts with water, while textural changes influence contact and liquid spreading at the surface. Designers can use either lever alone or combine them, allowing wettability to be adjusted without changing the filament’s underlying material or form.
The switching mechanism links a change in surrounding conditions or an applied stimulus to a change in surface behavior. That response can move the filament from water-repelling behavior toward greater wettability, or reverse the change when conditions are adjusted again. The important engineering feature is controllable, reversible regulation rather than a permanently modified surface.
Reversibility allows one filament to perform different surface functions during changing operating conditions. A surface can regulate liquid spreading, absorption, adhesion, or transport as requirements shift, while the underlying filament remains in place. This reduces the need to replace the structural element and supports adaptive material designs for environments where a single fixed wettability would be limiting.
A basic design workflow begins by identifying the required liquid behavior, then selecting surface chemistry, texture, or a combination of both as the control mechanism. The engineer next connects that surface design to an external condition or applied stimulus and evaluates whether the filament changes between the intended states. Testing should focus on switching behavior and the resulting fluid interaction.
The switching approach is preferable when a device must alternate between repelling water and interacting more readily with it. A permanently hydrophobic filament provides one stable surface response, whereas a switchable design can adapt liquid spreading, absorption, adhesion, or transport to changing conditions. This distinction is especially relevant to responsive fibers, smart textiles, and fluid-handling systems.
Potential applications include responsive fibers, engineered coatings, filtration systems, fluid-handling devices, and smart textiles. In each case, the controllable surface response can help manage how liquids spread, enter, adhere to, or move through a material. The approach therefore connects surface engineering with adaptive performance, particularly when the surrounding environment or operating requirement changes over time.