New formula predicts water resistance of materials without costly lab tests
Researchers have discovered a simple mathematical relationship that can determine how water-repellent or water-attracting a material surface is by analyzing molecular movement rather than traditional contact angle measurements. The finding could accelerate development of better coatings, waterproofing, and industrial materials by cutting testing time and costs.
Originaltitel: Diffusion-Wetting: a universal molecular relation
<p>Quantifying wettability at the nanoscale remains challenging because apparent macroscopic contact angles average over multiple surface-specific effects such as roughness, chemical heterogeneity, and defect/pinning, thereby obscuring the underlying microscopic hydrophilic or hydrophobic response. We derive an analytical relation linking the microscopic water contact angle to the lateral diffusion of interfacial molecules, establishing a quantitative connection between water dynamics and the wetting behavior. Molecular dynamics simulations confirm that the ratio of interfacial to bulk diffusion uniquely determines the contact angle across the full hydrophilic-hydrophobic spectrum. This diffusion-based formulation eliminates the need for droplet geometries or free-energy sampling, enabling quantitative assessment of wetting directly from equilibrium molecular dynamics trajectories, which for simple interfaces can be remarkably short. The approach provides a universal and efficient route to evaluate surface affinity in reactive, defective, or confined environments.</p>