Liquid-repellence ✖ György

Background reading music curated for this article is available at the bottom. Click to enjoy

01 Introduction - Background

Water-proof takes a critical role in providing convenience in our daily life. From raincoats to digital device protection boxes, material’s water-proof characteristic protects the valuables and ourselves from erosions of water.

raincoats with water-proof layers

Interestingly, most our water-proof focuses on the processing on the material itself to “repel” water rather than absorbing it. Have you ever thought about doing some work on the water? For example, is there ever possibility to make the water “reluctant” to be absorbed by materials and just slide away? Of course there is and this technique is called Liquid-repellent particle coating.       

02 Traits - What makes liquid-repellent particle coating stand out

This particle coating is loaded on the surface of liquid drops rather than surfaces of objects exposed to water. The main component of this material is fluorocarbon-modified fumed titania. Unlike ordinary particles, this material possesses an extremely low surface energy due to the presence of fluorocarbon chains on its surface. 

how liquid-repellent particle coating works

Such a property makes the particles highly unfavorable to both water and oils. When these particles attach themselves to the outer surface of liquid droplets, they form a protective shell that prevents direct contact between the liquid and surrounding materials. As a result, the liquid becomes difficult to wet or penetrate surfaces, allowing droplets to retain their shape and slide away easily under external forces.

03 Synthesis – How the film is made

So, how can we make fluorocarbon-modified fumed titania? Fluorocarbon-modified fumed titania is synthesized through a surface-modification process that alters only the outer chemistry of the particles while preserving the original titania core. 

surface modification

Fumed titania particles naturally possess a large number of hydroxyl (–OH) groups on their surfaces, which serve as reactive sites for chemical attachment. In the modification process, fluorocarbon-containing compounds—most commonly fluorinated silanes—are introduced to react with these surface hydroxyl groups through a condensation reaction. 

（插图）fluorinated silane - hydroxyl group reaction

During this reaction, strong Ti–O–Si bonds are formed, anchoring the modifier firmly onto the titania surface, while the fluorocarbon chains extend outward. After excess modifier is removed and the material is dried, the resulting particles exhibit extremely low surface energy due to the presence of fluorocarbon groups. This synthesis method effectively transforms hydrophilic fumed titania into a highly water- and oil-repellent material without changing its particle size, crystal structure, or high surface area.

04 Application - Potential Usage

Liquid-repellent particle coatings are widely applied across multiple fields due to their ability to prevent liquids from wetting, spreading, or adhering to surfaces. In construction and infrastructure, they are used for self-cleaning facades, water-resistant concrete, and anti-corrosion surfaces, reducing maintenance costs. In textiles and consumer products, these coatings provide waterproof, stain-resistant fabrics and protective layers for electronics against accidental spills. In the medical and healthcare sector, liquid-repellent coatings help minimize biofouling and contamination on surgical tools and devices. What’s more, they are also valuable in energy and environmental applications, such as self-cleaning solar panels and oil–water separation materials.

Want some music?

This time I feel like recommending György Ligeti's Sonata for Solo Cello I. Dialogo.

György Ligeti's Sonata for Solo Cello （1948-53）-Dialogo

4:55

It has an eerie smoothness and restraint. The sound feels suspended, almost untouchable, with long, sliding lines that never quite “settle” or cling to the ground. That sense of controlled distance matches the idea of liquid being repelled—close contact is suggested, but true adhesion never happens.