Substrate effect on latex particle self-arraying: a SEPM study

Sub-monolayers of PS-AAM latex particles were examined by scanning electric potential microscopy (SEPM), non-contact atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM). The micrographs revealed domains of positive or negative potentials within the individual particles and aggregates, forming multipoles. All the particle multipoles have the same relative orientation in the image plane and they are aligned with the mica a crystallographic axis. Particle alignment is interpreted considering the polarization anisotropy in the mica (001) plane: the deposited particles rotate, until the particle dipole-mica induced dipole interaction energy is minimum.