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Research Article

Ceramic Nanoparticle/Monodisperse Latex Coatings

Supporting Info

Hui Luo^†, Christine M. Cardinal, L. E. Scriven^‡ and Lorraine F. Francis*

Department of Chemical Engineering & Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA

Langmuir, 2008, 24 (10), pp 5552–5561

DOI: 10.1021/la800050u

Publication Date (Web): April 17, 2008

†

Present address: Brady Corporation, 2230 West Florist Avenue, Milwaukee, WI 53209.

‡

Deceased, 2 August 2007.

* To whom correspondence should be addressed. Tel: 1-612-625-1313 . Fax: 1-612-626-7246. Email: lfrancis@umn.edu.

Abstract

Ceramic nanoparticle/monodisperse latex coatings with a nanoparticle-rich surface and a latex-rich body were created by depositing aqueous dispersions of monodisperse latex, 550 nm in diameter, and nanosized ceramic particles onto substrates and drying. On the top surface of the dried coating, the latex particles are closely packed with nanoparticles uniformly occupying the interstitial spaces, and along the cross section, nanoparticles fill the spaces between the latex particles in the near surface region; a compacted latex structure, nearly devoid of nanoparticles, lies beneath. Cryogenic scanning electron microscopy images of partially dried coatings at successive drying stages reveal two important steps in forming this structure: top-down consolidation of latex particles and accumulation of nanoparticles in interstitial spaces among latex particles near the surface. A systematic study of the effect of processing conditions, including nanoparticle concentration, nanoparticle size, latex glass transition temperature, and drying conditions, on the final microstructure was carried out. The unique microstructure described above forms when the monodisperse latex is large enough to create pore channels for the transport of nanosized particles and the drying conditions favor “top-down” as opposed to “edge-in” drying.