London-van der Waals Force Field of a Chemically Patterned Surface To Enable Selective Adhesion

Area of Science:

• Surface Science
• Colloid and Interface Science
• Nanotechnology

Background:

• London-van der Waals (L-vdW) forces govern particle-surface interactions.
• Surface topography's effect on L-vdW adhesion is well-studied.
• The role of chemical heterogeneity in L-vdW forces is less understood.

Purpose of the Study:

• To quantify the magnitude and range of L-vdW forces on particles near chemically patterned surfaces.
• To investigate the influence of chemical heterogeneity on particle adhesion.
• To explore the potential of L-vdW forces for particle manipulation.

Main Methods:

• Modeling an ideal system of a spherical particle and a striped surface with distinct Hamaker constants.
• Solving the London dispersion potential from first principles using Hamaker's microscopic approach.
• Computational analysis of L-vdW forces, including normal and tangential components.

Main Results:

• A tangential L-vdW force component arises from chemical interfaces, inducing lateral particle motion.
• Tangential force is maximal at the chemical interface and decreases with distance.
• Significant tangential forces occur for large colloidal particles near patterned surfaces with differing Hamaker constants.

Conclusions:

• Chemically patterned surfaces generate tangential L-vdW forces that can control particle trajectories.
• This tangential force can be harnessed for selective particle adhesion and manipulation.
• Understanding chemical heterogeneity is crucial for predicting and controlling particle-surface interactions.