Non-Arrhenius kinetics and slowed-diffusion mechanism of molecular aggregation of a rhodamine dye on colloidal particles

Abstract

The non-covalent association is important for many fields of science, including processes in living systems. This work elucidates the mechanism of rhodamine 123 molecular aggregation in dispersions of a layered...

Adsorption of Dye Molecules and Its Potential for the Development of Photoactive Hybrid Materials Based on Layered Silicates

“…(A) Scheme showing the mechanism of the redistribution and aggregation of adsorbed dye molecules and (B) temperature dependence of the rate constants of the simultaneous diffusion processes occurring in dye/layered silicate colloidal systems. Reproduced from ref with permission from the PCCP Owner Societies. Copyright 2021.…”

“…For diffusion to take place, it is necessary to overcome the energy barrier between an adsorbed molecule and an adsorption site. During diffusion on the surface, the adsorbed molecule never completely loses contact with the particle . The continuous interaction between the adsorbed molecule and the particle is mediated by attractive forces.…”

“…The same mechanism applies even for the surface diffusion of large organic molecules with a planar structure, for which a strong bond with the substrate was assumed, as reported for a perylene derivative on a semiconductor surface . A similar mechanism has been proposed for the lateral diffusion of solvent molecules in contact with the surface, which may secondarily affect the mobility of the adsorbed molecules. The other process observed for the aggregation of R123 dye molecules is interparticle diffusion . In this case, a dye molecule must acquire sufficient energy to not only get released from the original adsorption site but also to leave the particle completely.…”

“…A detailed analysis was carried out for colloidal systems based on layered silicate nanoparticles with adsorbed rhodamine 123 (R123) cations . The processes related to the redistribution of molecules initially adsorbed on the free surface of particles were characterized by rather complex mechanisms. , In addition to the sorbate–sorbent interactions, the processes were influenced by the bonds between the sorbate and solvent molecules, the sorbent-solvent interactions, the interactions between the colloidal particles themselves, and, finally, the interactions between the sorbate molecules. Although the redistribution of the adsorbed molecules is mainly observable for dyes, due to their specific optical properties, it is likely to be a universal process following the adsorption in a huge variety of colloidal systems.…”

Free Energy Surfaces and Barriers for Vacancy Diffusion on Al(100), Al(110), Al(111) Reconstructed Surfaces

“…Al is of particular interest recently due to its exceptional properties [ 34 , 35 , 36 , 37 , 38 , 39 ]. On the other hand, defects like vacancy are omnipresent on crystals and play an important role in their properties [ 40 , 41 , 42 , 43 , 44 ]. Substantial experimental and theoretical efforts have been employed over many years to elucidate the free energy surfaces and free energy barriers of diffusion on crystal surfaces [ 45 , 46 , 47 , 48 ].…”