Arrest of morphological transformation during evaporation-induced self-assembly of mixed colloids in micrometric droplets by charge tuning
Debasis Sen,Jose Savio Melo,Jitendra Bahadur,Subhasish Mazumder,Shovit Bhattacharya,Stanislaus Francis D'Souza,Henrich Frielinghaus,Günter Goerigk,Rudolf Loidl
Soft Matter Pub Date : 05/09/2011 00:00:00 , DOI:10.1039/C1SM05100H
Abstract

Self-assembled grains of mixed colloids have been synthesized using evaporation induced self-assembly (EISA) by spray drying. We demonstrate using electron microscopy and small-angle neutron scattering experiments that buckling driven sphere to deformed-doughnut like morphological transformation in such a process can be arrested by proper tuning of the surface charge on the colloidal components. The buckling amplitude diminishes with a reduction in stabilization force between the colloidal particles. It is established that such arrest of morphological transformation is related to an effective exposure of the surface of softer component at gas–liquid interface. Scattering experiments confirm relatively more compact structure of the non-buckled grains compared to that of the buckled grains. A plausible mechanism regarding the arrest of morphological transformation by surface charge tuning is illustrated.

Graphical abstract: Arrest of morphological transformation during evaporation-induced self-assembly of mixed colloids in micrometric droplets by charge tuning