Polymer/surfactant assisted self-assembly of nanoparticles into Langmuir-Blodgett films

We studied the ability of poly(octadecene-co-maleic anhydride) (PMAO) and a Gemini surfactant [C18H57 (CH3)(2)N+Br--(CH2)(2)-N+Br-(CH3)(2) C18H37] (18-2-18) to assist in the self-assembly process of CdSe quantum dots (QDs) at the air water interface. Results show that, while QD agglomeration is generally inhibited by the addition of these components to the Langmuir monolayer of QDs, structure of the film transferred onto mica by the Langmuir-Blodgett method is strongly affected by the dewetting process. Nucleation-and-growth of holes and spinodal-like dewetting were respectively observed in the presence of either PMAO or 18-2-18. When PMAO/18-2-18 mixtures were used, both mechanisms were allowed; nevertheless, even in films prepared with mixtures of low polymer contents, characteristic morphology from the polymer dewetting route prevailed. (C) 2012 Elsevier B.V. All rights reserved.