Influence of interparticle structuring on the surface energetics of a binary powder system.

The structuring of component particles in binary compositions affects the solid-solid interfacial properties. This work reports the effect of interparticle interactions in binary powder compositions of D-Mannitol and glass beads through the heterogeneity data obtained from Finite Dilution Inverse Gas Chromatography (FD-IGC). Three different scenarios viz. structured, random and segregated systems of the binary powder composition were considered for the analysis in the IGC column. Binary mixtures with large size disparity between the components produced structured mixtures exhibiting a guest-host type of interactions and energetic homogeneity irrespective of the energetics of the finer component. Random and segregated systems revealed a heterogeneous trend in the data indicating preferential probing of the active sites of the composition, particularly at the lower probe coverages. The results demonstrate that in the multicomponent binary systems the surface energetics is influenced by the solid-solid interfaces and structuring of the component particles within the mix i.e., the surface energy analysis could reveal a mixing behavior in powders. Furthermore, an adsorption energy distribution model based on Boltzmann statistics and simulation fitting approach was employed to deconvolute the distribution of the changing energy landscape of the binary mixtures.