Particles aggregations in liquid are of great interest because the random collisions of particles are sometimes accompanied with directional assembly, leading to the formation of highly ordered structures. In this work, we find a easy method to synthesize diamond-shaped silver nano particles in gels solution. The time dependent structure characterization indicates that these diamond shape particles were assembled by the spontaneous aggregation of tiny primary Ag clusters. Since the diffusion of Ag clusters are limited in viscous gels solution, Each cluster approaching to the aggregates has more sufficient time and space to optimize its location. The minimization of surface free energy leads to a selective binding of two approaching nuclei. The high energy facets of each nuclei have priority to be the receiving surface for aggregation, while the low energy facets are largely exposed in the aggregation, which led to a oriented self-assembling of Ag clusters. The findings in this paper indicate that the diffusion of building blocks plays an important role in the shape development of materials.

Figures:

(A) TEM images of one diamond-shaped Ag particle formed in an agar gel system (with silver ion 0.5wt% and agar gel 0.5wt%). (B) Corresponding SAED pattern of the particle in figure A. (C) TEM images of many diamond-shaped Ag particles

The time dependent evolvement of diamond-shaped silver particles in an agar gel solution

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EMC Abstracts - https://emc-proceedings.com/abstract/diamond-shape-formation-by-spontaneous-aggregation-of-silver-clusters-in-gels/