Nano2Micro: Water Droplets & Surfaces

Water is a uniquely anomalous substance, exhibiting extraordinary physical and chemical behavior - especially at the microscale. From the freezing of pure water droplets and ice nucleation in supercooled states to the uptake of gases and nanoparticles at aqueous interfaces, processes involving single micron-sized water particles remain among the most challenging and least understood phenomena in modern science. These processes are central to atmospheric physics, cloud formation, biophysics, and soft matter systems, yet their molecular origins are often obscured by complexity and scale.

This focus group brings together experts from physics, chemistry, atmospheric science, mathematics, and computer science to unravel the fundamental mechanisms governing single water particles—whether liquid, solid, or in transition. By integrating ultrafast experiments, molecular dynamics simulations, and advanced theoretical modeling, we aim to decode how water’s structure, dynamics, and reactivity evolve under extreme conditions and at interfaces.

Our interdisciplinary approach addresses critical questions: How does water freeze without impurities? What drives ice nucleation on specific substrates? How do solutes, nanoparticles, or polymers alter water’s local structure, viscosity, and reactivity? How do chemical reactions proceed within confined droplets or at air-water interfaces? We are particularly interested in bridging the gap between molecular-scale dynamics and macroscopic observables - such as nucleation rates, refractive index changes, and surface charge effects - through multiscale modeling and data-driven methods.

By fostering collaboration across JGU Mainz, the Max Planck Institutes (MPIP, MPIC), and the broader Rhine-Main University (RMU) network, we aim to establish a vibrant research hub for microscale water science. Our work will deepen our understanding of one of nature’s most essential substances and unlock new pathways in climate science, materials design, and biomedical applications.

Research Scope

Ice Nucleation & Freezing: Homogeneous and heterogeneous nucleation mechanisms in pure and aqueous droplets
Interfacial Water Dynamics: Structure, reactivity, and charge transfer at air-water, liquid-solid, and liquid-vapor interfaces
Chemical Reactivity in Droplets: Uptake and transformation of volatile compounds, aerosol chemistry, and surface reactions
Nanoparticle & Polymer Uptake: Interactions of nanoparticles and soft matter with water particles and their impact on stability and function
Molecular Dynamics Simulations: Atomistic modeling of water structure, hydrogen bonding, and transport in confined environments
Theoretical & Mathematical Modeling: Non-equilibrium thermodynamics, nucleation theory, and multiscale modeling of microscale processes
Advanced Experimental Techniques: Cryogenic microscopy, ultrasonic trapping, microjet generation, and in situ spectroscopy
Data-Driven Science: Machine learning for predicting nucleation pathways and interpreting complex experimental data