DLVO interaction energies between hollow spherical particles and collector surfaces

Authors: SHEN, CHONGYANG - China Agricultural University; Bradford, Scott; WANG, ZHAN - China Agricultural University; HUANG, YUANFANG - China Agricultural University; ZHANG, YULONG - Shenyang Agricultural University; LI, BAOGUO - China Agricultural University

Submitted to: Langmuir
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2017
Publication Date: 9/19/2017
Citation: Shen, C., Bradford, S.A., Wang, Z., Huang, Y., Zhang, Y., Li, B. 2017. DLVO interaction energies between hollow spherical particles and collector surfaces. Langmuir. 33:10455-10467. http://pubs.acs.org/doi/abs/10.1021/acs.langmuir.7b02383.

Interpretive Summary: This manuscript examines potential advantages of hollow colloids in comparison to solid colloids that can be exploited in environmental and industrial applications. In particular, an approach was developed to determine the interaction of various types of hollow colloids with surfaces. Results reveal that hollow colloids typically exhibited a weaker interaction with surfaces than solid colloids. Consequently, they are expected to exhibit greater subsurface mobility and weaker aggregates than solid colloids. This information will be of interest to scientists and engineers concerned with using colloids and nanoparticles to remediate subsurface hazardous waste sites.

Technical Abstract: The surface element integration technique was used to systematically study Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies/forces between hollow spherical particles (HPs) and a planar surface or two intercepting half planes under different ionic strength conditions. The inner and outer spheres of HPs were concentric (CHP) or in point contact (PHP). In comparison to a solid particle, the attractive van der Waals interaction was reduced with increasing inner radius of the CHP, but the reduction effect was less significant for the CHP at smaller separation distance. Increasing the inner radius for CHP therefore reduced the depths of the secondary minima, but had minor influence on the energy barrier heights and depths of the primary minima. Accordingly, increasing inner radius reduced the potential for CHP retention in secondary minima, whereas did not influence the retention in primary minima. For PHP these interaction energy parameters and colloid retention depended on the orientation of the inner sphere relative to interacting surface. In particular, the van der Waals attraction was significantly reduced at all separation distances when the inner sphere was closest to the interacting surface, and this diminished retention in both secondary and primary minima. The PHP retention was similar to that of CHP when the inner sphere was farthest from the interaction surface. These orientation dependent interaction energies/forces resulted in directional bonds between PHPs and the formation of aggregates with contact points of the primary PHPs facing outward. These findings have important implications for the design and utilization of HPs in soil remediation and colloid assembly.