title: Use of small-angle neutron scattering to investigate modifications of internal structure in self-assembled grains of nanoparticles synthesized by spray drying.
abstract: Micrometric spherical grains consisting of self-assembled silica nanoparticles have been synthesized by spray drying of colloidal suspension. Inter-particle correlation and available specific surface area of silica and void interfaces, in the assembled grains, were modified by addition of electrolyte in initial colloidal dispersion prior to self-assembly process but keeping the overall spherical shape of the assembled grains un-altered. While the external morphology of the assembled grains was probed by scanning electron microscopy, small-angle neutron scattering technique has been employed to investigate the modifications in the internal structure and the inter-particle correlation inside the assembled grains. It is revealed that a sticky hard sphere type of inter-particle correlation between the constituent particles gets altered to a fractal type of correlation with addition of electrolyte. Further, the specific surface area of the silica-void interface gets somewhat enhanced by addition of electrolyte and particularly at higher electrolyte concentration due to formation of some hollow and buckled assembled grains.
authors.affiliation: Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. debasis@barc.gov.in
authors.forename: D
authors.initials: D
authors.lastname: Sen
authors.forename: Arshad
authors.initials: A
authors.lastname: Khan
authors.forename: J
authors.initials: J
authors.lastname: Bahadur
authors.forename: S
authors.initials: S
authors.lastname: Mazumder
authors.forename: B K
authors.initials: BK
authors.lastname: Sapra