Ion-Triggered Exfoliation Method for the Fabrication of Layer-by-Layer Assembled Free-Standing Multilayer Films

摘要

@@Layer-by-layer (LbL) assembled multilayer films have attracted much attention in the recent decade because of their potential applications as separation membranes, sensors, optical and electronic film devices, and so forth. The LbL assembled multilayer films are usually deposited on solid substrates which provide firm support but can meanwhile produce an influence on their properties. The preparation of LbL assembled flee-standing multilayer films which exist without solid substrates is meaningful because of the following: (i) Free-standing films make it possible to investigate directly the elastomeric properties of the LbL assembled films. (ii) Free-standing films are expected to broaden further the application of LbL assembled multilayer films, especially as separation membrances,sensors, catalytic film, micromechanical devices, or even artificial organs. There have been two main methods for the preparation of flee-standing LbL assembled films. The most frequently used and generally applicable method is using a predeposited sacrificial layer between the substrate and the LbL assembled films. Free-standing films can be released from the substrate by dissolving the sacrificial layer in a selected solution. Removal of the substrate provides another straightforward method to prepare free-standing multilayer films. Although the above-mentioned methods work well for most of LbL assembled multilayer systems to prepare free-standing films, facile methods without the use of sacrificial layer or complete removal of substrate are still highly desirable.