la302201g_si_001.pdf (80.83 kB)
Theoretical Investigation on the Steric Interaction in Colloidal Deposition
journal contribution
posted on 2012-10-30, 00:00 authored by Shihong Lin, Mark R. WiesnerA theoretical investigation was conducted upon the steric
interaction
between a spherical particle and a flat plate. The effects of curvature
on both the segment density distribution of polymer and on the steric
interaction energy between a particle and a plate were examined. It
was found that the conventional approach using Derjaguin approximation
may overestimate the interaction energy, especially for very small
particles. Based on the results obtained from applying the Flory–Krigbaum
theory with the accurate geometry change during the interaction, simple
approximate expressions of exponential form were proposed for both
the osmotic (mixing) and elastic contributions to the steric interaction
energy for a sphere-plate interaction. The proposed model was validated
against a set of experimental results from a reported study employing
atomic force microscopy. Also investigated was the steric interaction
between a spherical particle coated with polymer and an uncoated flat
surface. It was found that the steric interaction energy from the
osmotic contribution is significantly higher than that from the elastic
contribution and that steric interaction is considerably weaker when
the polymer exists on only one of the interacting surfaces.