title: Effect of soluble polymer binder on particle distribution in a drying particulate coating.
abstract: Soluble polymer is frequently added to inorganic particle suspensions to provide mechanical strength and adhesiveness to particulate coatings. To engineer coating microstructure, it is essential to understand how drying conditions and dispersion composition influence particle and polymer distribution in a drying coating. Here, a 1D model revealing the transient concentration profiles of particles and soluble polymer in a drying suspension is proposed. Sedimentation, evaporation and diffusion govern particle movement with the presence of soluble polymer influencing the evaporation rate and solution viscosity. Results are summarized in drying regime maps that predict particle accumulation at the free surface or near the substrate as conditions vary. Calculations and experiments based on a model system of poly(vinyl alcohol) (PVA), silica particles and water reveal that the addition of PVA slows the sedimentation and diffusion of the particles during drying such that accumulation of particles at the free surface is more likely.
authors.affiliation: Institute of Thermal Process Engineering, Thin Film Technology, Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, D-76131 Karlsruhe, Baden-Württemberg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Buss
authors.forename: Christine C
authors.initials: CC
authors.lastname: Roberts
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Crawford
authors.forename: Katharina
authors.initials: K
authors.lastname: Peters
authors.forename: Lorraine F
authors.initials: LF
authors.lastname: Francis
mesh_terms: D010316:Particle Size; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties
chemical_list: D011142:Polyvinyl Alcohol