How Bulk Chemistry Affects Surface Adaptation

Benjamin Leibauer
Přednáška hosta ústavu
24.6.2025 10:00, Přednáškový sál A

The wetting properties of materials play a crucial role for example in biology or industrial processes and applications. While the surface is in contact with the liquid, the wetting properties can change. The change of the wetting properties in contact with a liquid is known as surface adaptation. To understand surface adaptation is important, to improve new coatings, optimize industrial processes such as the fabrication of materials or printing. For polymer surfaces, swelling or reorientation of the polymer surface results in surface adaptation. Here we synthesized grafted hydrophilic-b-hydrophobic diblock copolymer brush surfaces. The thickness of the hydrophobic and hydrophilic block was varied to study the surface adaptation behavior in contact with water. For diblock copolymer surfaces, with a hydrophobic layer above ≈25 nm, no surface adaptation was observed. Below the thickness of ≈25 nm of the hydrophobic block, the diblock copolymer brush surfaces adapt to water. Exposing the diblock copolymer brush surface with a hydrophobic layer above ≈25 nm, we were able to switch the wetting behavior reversible from hydrophobic to hydrophilic. It is known that sliding drops over a hydrophobic surface get charged. The counter charges stay on the surface and the surface gets charged. This phenomenon is called slide electrification. However, the role of surface adaptation in slide electrification has not been investigated yet. We fluorinated different silicate glasses with a 1-3nm thick hydrophobic layer. The fluorinated surfaces were analyzed by measuring the charge of sliding drops. Compared to the monochlorsilane coated surface, the drop charge on the trichlorosilane coated surfaces correlated to the substrate properties and we were able to show that surface adaptation affect slide electrification.

Přednáška je vedena v anglickém jazyce