SPP 2171 Spring Conference: Dynamic Wetting of Flexible, Adaptive, and Switchable Substrates

Polymer brushes with infused lubricants show significant potential in reducing drop adhesion, yet the depletion of lubricant hinders its durability and the underlying mechanisms remain poorly understood. Our study focuses on observing and analyzing drop-induced lubricant depletion process on Poly Lauryl Methacrylate (PLMA) brushes with dimple and wetting ridge forming. We achieved...

The accumulation of dust on surfaces is a well-known phenomenon in everyday life, for example on windows and solar panels. Both manual cleaning and self-cleaning of hydrophobic surfaces with water can restore the properties of soiled surfaces. However, it is not yet understood how particles are removed by a water drop and which forces play a role for successfully removing the particles. We...

Water drops spontaneously become electrically charged when moving on different surfaces, such as plant leaves, building walls, window glass, and plastic. This process is called contact or slide electrification. The electric potential of water drops charged in this way can even exceed 1 kV. A vital question as yet unanswered is whether the charge in water drops generates corrosion. Here, we...

The understanding of wetting phenomena plays a crucial role in many daily processes. For example, dirt repelling glasses can be achieved by a hydrophobic coating. Typically, the wetting properties of such a coating are characterized by measurements of the advancing and receding contact angles by sessile drop goniometry [1]. However, this method provides only information on the selected areas...

Wetting phenomena are of great importance across various scientific disciplines, and as a fundamental research area, the wettability dynamics of adaptive substrates, such as polyelectrolyte multilayers (PEM), have gained significant attention. Notably, an interesting property of polyelectrolyte (PE) substrates is their propensity to swell in a liquid environment. However, the complexities such...

Block copolymer gradient brushes: A detailed look at the synthesis and characterization

Jonah Decker1, Sören Steup2, Sergey I. Druzhinin1, Heiko Ihmels2, Holger Schönherr1*

1 Physical Chemistry I, Department of Chemistry and Biology and Research Center of Micro and Nanochemistry and (Bio)Technology (Cμ),...

Nanoscale poly(dimethylsiloxane) (PDMS) layers prepared by grafting the polymer chains on a smooth solid surfaces are typical example for the so called slippery covalently-attached liquid surfaces (SCALS). Such surfaces exhibit very low contact angle hysteresis (CAH) and low friction for sliding water drops [1-2]. These properties are commonly attributed to the liquid-like mobility of the...

Wetting is generally regarded as an inherent property of material surfaces. Wetting imperfections contribute to contact angle hysteresis, influencing the overall wetting dynamics. Existing techniques like contact angle goniometry are not sufficient for accurately quantifying variations in wetting behavior due to temporal and local resolution limitations. A direct quantitative measurement of...

High-speed side-view videos of sliding drops enable researchers to investigate drop dynamics and surface properties. However, understanding the physics of sliding requires knowledge of the drop width, which necessitates a front-view perspective. The drop’s width is a crucial parameter due to its association with the friction force. Incorporating extra cameras or mirrors to monitor changes in...

The interaction of liquid droplets with lubricated substrates is rich with interesting physics combining thermodynamics, polymer science, and fluid dynamics, and has the potential for various industrial applications. In previous work, we showed the existence of a cloaking transition where the lubricant covers the surface of the droplet at equilibrium. Here, we describe the kinetics of the...

The advancement of renewable energies is crucial in an age in which we are confronted with growing climate and environmental challenges. Solar energy is considered a highly promising, efficient and environmentally friendly source of energy. However, solar panels lose a significant amount of efficiency due to soiling [1]. Thus, a lot of water (more than 35 billion liters per year) is required...

We designed and fabricate stimulus responsive polymer brushes which can switch the chain conformation reversibly in response to addition/removal of small amount of Cd2+ions. Design of the polymer structure was inspired by plant protein (phytochelatin) that selectively detect and capture Cd2+ ions. As our polymer realized an excellent affinity to Cd2+ (KD ~ 10-9 M), the brush conformation and...

Synthesis and investigation of Nile Red- and aurone-labeled methacrylate derivatives as novel solvatochromic probes for polymer analysis

Sören Steup1, Jonah Decker2, Sergey I. Druzhinin2, Daria V. Berdnikova1, Holger Schönherr2, Heiko Ihmels1*

1 Organic Chemistry II, Department of Chemistry and Biology and Research Center of Micro and Nanochemistry and (Bio)Technology (Cμ), University...