Deposition of nanosized latex particles onto silica and cellulose surfaces studied by optical reflectometry.
Deposition of positively charged nanosized latex particles onto planar silica and cellulose substrates was studied in monovalent electrolyte solutions at pH 9.5. The deposition was probed in situ with optical reflectometry in a stagnation point flow cell. The surface coverage can be estimated reliably with island film theory as well as with a homogeneous film model, as confirmed with atomic force microscopy (AFM). The deposition kinetics on the bare surface was of first order with respect to the particle concentration, whereby the deposition rate was close to the value expected for a perfect collector. The efficiency coefficient, which was defined as the ratio of the experimental and theoretical deposition rate constants, was in the range from 0.3 to 0.7. Subsequently, the surface saturated and a limiting maximum coverage was attained (i.e., blocking). These trends were in qualitative agreement with predictions of the random sequential absorption (RSA) model, where electrostatic interactions between the particles were included. It was observed, however, that the substrate strongly influenced the maximum coverage, which was substantially higher for silica than for cellulose. The major conclusion of this work was that the nature of the substrate played an important role in a saturated layer of deposited colloidal particles.
Kleimann
Jörg
J
Department of Inorganic, Analytical, and Applied Chemistry, University of Geneva, Science II, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
Lecoultre
Guy
G
Papastavrou
Georg
G
Jeanneret
Stéphane
S
Galletto
Paolo
P
Koper
Ger J M
GJ
Borkovec
Michal
M
D002482:Cellulose / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007840:Latex / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D053758:Nanoparticles / Q000737:chemistry*; D055095:Optics and Photonics; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
D007840:Latex; D012822:Silicon Dioxide; D002482:Cellulose