The capacity of nanoparticles to self-arrange to various structures and their unique physical properties has made these building blocks essential in a broad range of applications and scientific disciplines. In this talk, we consider the manipulation of particulate structures that appear from binary particulate dispersions, comprising same size particles of two different chemistries. By varying the ionic strength and pH in the volatile carrier liquid, we tune the balance between attractive and repulsive surface forces – electrical double layer, Van der Waals, hydrophobic, and hydrophilic forces – in the suspensions. The combination of surface forces supports corresponding potential energy barriers to particle-particle attachments and to particle-substrate attachments. By tuning the energy barriers, we alter the nanoscopic to mesoscopic arrangement of the different types of particles in the particulate structures to appear in the process of convective pattern formation during the evaporation of the carrier liquid. Realizing the physical mechanisms which govern the potential energy contributions to the pattern formation of particulate structures at the nano-meter scale, we render the 3D morphology of the particulate mixtures homogeneous, layered, or phases segregated. In this work we attempt to introduce a useful approach toward the top-down fabrication of nonhomogeneous colloidal structures.

Signatures of molecular surface forces in the self-assembly of binary mixtures of nanoparticles on a solid substrate

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.