Meso- and Microscopic Behavior of Spherical Polymer Particles Assembling at the Air−Water Interface

Abstract

Using the Langmuir Blodgett (LB) technique, monolayers of spherical polymer particles were investigated at the air−water interface. In this study, LB methods were used to examine particle interactions, packing, morphology, and viscosity of polymer films. Films composed of polymer microgels (diameters of 113−427 nm) having a block-copolymer dispersant were investigated through isotherm, atomic force microscopy imaging, and two-dimensional (2D) viscosity studies. During monolayer formation, the effect of the dispersant and particle size on the behavior of the isotherms was examined. The contact cross-sectional area of the isotherms for these spheres was compared to the ideal hexagonal close packing (hcp) model. Initial investigations concerning the flow properties of the particles in 2D slurries were also performed. In addition, spherical hyperbranched polymer particles (≈60 nm) with and without a modified hydrophilic surface were also studied using isotherm and hysteresis experiments and the hcp model. Both of these studies may show the influence of surface composition and particle size on the interaction of polymer particles at the air−water interface.