(176g) Unexpected Correlations Observed in Two-Dimensional Ordered Arrays of Colloidal Particles Deposited on Patterned Polyelectrolyte Multilayer Surfaces

Hur, J. - Presenter, Purdue University

Our recent study demonstrates that two-dimensional (2-D) periodic patterns of polyelectrolyte multilayers (PEM's) can be used as surface templates for assembling highly ordered 2-D colloidal micro arrays (which could then be used as structural templates for epitaxially growing three-dimensional colloid crystals thereon). In this presentation, we will discuss detailed structural features of the 2-D ordered layers of charged microspheres deposited to the oppositely-charged PEM patterns. Particularly, this talk will discuss two unexpected observations that are revealed by statistical image analysis of the 2-D colloid arrays: (i) the distribution of the distances by which the adsorbed particles deviate from the corresponding PEM pattern centers is neither random nor electrostatically governed; (ii) the distribution of the vectors defining the off-centering positions of the particles are correlated over all length scales up to the sample size (i.e., of the millimeters), and display an anomalous transition from positive(i.e.,parallel) to negative(i.e.,anti-parallel) correlation with increasing distance. Possible explanations for the observed behavior will be presented.