Free-standing layer-by-layer assembled films of magnetite nanoparticles

Abstract

A new technique for preparation of free-standing ultrathin films is presented. These films were made by layer-by-layer (LBL) deposition process, which is utilized for coatings on solid substrates and colloids. A film composed of alternating layers of magnetite nanoparticles and poly(diallydimethylammonium bromide) was assembled on cellulose acetate, which was subsequently dissolved in acetone. From the suspended state, the LBL film can be transferred onto any solid or porous support. The strength of the film was observed to significantly increase when every other layer of magnetite was replaced with a layer of alumosilicate sheets serving as a molecular framework for the assembly.