Freestanding nanostructures via layer-by-layer assembly

Freestanding flexible nanocomposite structures fabricated by layer-by-layer (LbL) assembly are promising candidates for many potential applications, such as in the fields of thermomechanical sensing, controlled release, optical detection, and drug delivery. In this article, we review recent advances in the fabrication and characterization of different types of freestanding LbL structures in air and at air/liquid and liquid/liquid interfaces, including micro- and nanocapsules, microcantilevers, freely suspended membranes, encapsulated nanoparticle arrays, and sealed-cavity arrays. Several recently developed fabrication techniques, such as spin-assisted coating, dipping, and micropatterning, make the assembly process more efficient and impart novel physical properties to the freestanding films.