la204161d_si_002.pdf (136.41 kB)
Control of Buckling in Colloidal Droplets during Evaporation-Induced Assembly of Nanoparticles
journal contribution
posted on 2016-02-22, 07:52 authored by J. Bahadur, D. Sen, S. Mazumder, B. Paul, H. Bhatt, S. G. SinghMicrometric grains of anisotropic morphology have been
achieved
by evaporation-induced self-assembly of silica nanoparticles. The
roles of polymer concentration and its molecular weight in controlling
the buckling behavior of drying droplets during assembly have been
investigated. Buckled doughnut grains have been observed in the case
of only silica colloid. Such buckling of the drying droplet could
be arrested by attaching poly(ethylene glycol) on the silica surface.
The nature of buckling in the case of only silica as well as modified
silica colloids has been explained in terms of theory of homogeneous
elastic shell under capillary pressure. However, it has been observed
that colloids, modified by polymer with relatively large molecular
weight, gives rise to buckyball-type grains at higher concentration
and could not be explained by the above theory. It has been demonstrated
that the shell formed during drying of colloidal droplet in the presence
of polymer becomes inhomogeneous due to the presence of soft polymer
rich zones on the shell that act as buckling centers, resulting in
buckyball-type grains.