Measured long-ranged attractive interaction between charged polystyrene latex spheres at a water-air interface
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Date
2006-08-15Author
Chen, Wei
Tan, Susheng
Huang, Zhoushen
Ng, Tai-Kai
Ford, Warren T.
Tong, Penger
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We report results of a systematic experimental study of interactions between charged polystyrene (PS) latex spheres at a water-air interface. Optical observations of stable bonded particle clusters and formation of circular chainlike structures at the interface demonstrate that the interaction potential is of dipole origin. Atomic force microscopy (AFM) is used to examine the distribution of charge groups on the colloidal surface. AFM phase images show patchy domains of size ~100 nm on the particle surface, indicating that the surface charge distribution of the PS spheres is not uniform, as is commonly believed. Such patchy charges can introduce fluctuating in-plane dipoles, leading to an attraction at short interparticle separations. A theoretical analysis is given to explain the mechanism for attractions between like-charged particles at the interface.
Citation
Chen, W., Tan, S., Huang, Z., Ng, T.-K., Ford, W. T., & Tong, P. (2006). Measured long-ranged attractive interaction between charged polystyrene latex spheres at a water-air interface. Physical Review E, 74(2), Article 021406. https://doi.org/10.1103/PhysRevE.74.021406