A Kinetic Model to Describe Nanocrystal Growth by the Oriented Attachment Mechanism

Abstract

The classical model of particle coagulation on colloids is revisited to evaluate its applicability on the oriented attachment of nanoparticles. The proposed model describes well the growth behavior of dispersed nanoparticles during the initial stages of nanoparticle synthesis and during growth induced by hydrothermal treatments. Moreover, a general model, which combines coarsening (i.e., Ostwald ripening) and oriented attachment effects, is proposed as an alternative to explain deviations between experimental results and existing theoretical models.

In situliquid-cell electron microscopy of colloid aggregation and growth dynamics

“…Some of the earliest experimental work in the field of nanoscale colloid aggregation and growth was performed by Weitz et al [13,14] and Lin et al [15,16] on systems of aqueous gold colloids undergoing irreversible kinetic aggregation to form tenuous, chainlike fractal structures. Since then, a rich theoretical and modeling framework has been developed with emphasis on kinetic models [17][18][19] and computer simulations with applications of the Smoluchowsky theory [20][21][22][23][24]. To this day, however, experimental work that captures the dynamics of nanoscale colloid assembly or crystallization is scarce [25], due in large part to the difficulty of in situ observation of complicated nanoscale phenomena in liquid media with an appropriate level of spatial and temporal resolution.…”

Experimental and theoretical approach of nanocrystalline TiO2 with antifungal activity

“…In this nonclassical crystallization process, the crystal formation, which is controlled by a monomer-by-monomer assembly, is replaced by a process involving the spontaneous self-organization of adjacent nanocrystals to share a common crystallographic orientation and coalescence; i.e., by the OA growth mechanism [37]. A kinetic model to describe the OA growth process of nanoparticles in colloidal suspensions was proposed [38] and other studies based on this mechanism were developed by Penn [39] and Xu et al [40].…”

Tailoring of heterostructures in a SnO2∕TiO2 system by the oriented attachment mechanism

“…The heterostructures thus obtained are usually formed only through classical growth strategies; 2-5 however, advances in the comprehension of nonclassical growth mechanisms [6][7][8][9] can shed light on synthesis strategies for this purpose. A special case is the oriented attachment ͑OA͒ mechanism [10][11][12][13][14] and, in this work, the main goal is to substantiate the mechanism as a way to tailor heterostructures.…”

“…However, similar works still focus on classical growth mechanisms, despite the recent interest evinced in nonclassical growth mechanisms. Recent reports 13,14 have presented kinetic models to describe oriented attachment, a nonclassical approach that has proved important in tailoring anisotropic nanostructures. 8,9,16,17 By this mechanism, two or more nanoparticles become attached to each other through crystallographic alignment and consequent boundary migration, making the process faster than the classical atom attachment on surfaces.…”

“…SnO 2 is also an interesting candidate for evaluating OA due to its extremely low solubility. 13 TiO 2 was synthesized by decomposition of a peroxotitanium complex under hydrothermal conditions, as described in detail by Ref. 22.…”