Month: September 2022

INTRAMOLECULAR FORCES. “Beside physical fields with longer range, there are also forces upon particle contact. Already two identical crystal faces can orient each other when brought in close contact, as was observed in the process of oriented aggregation. The principal attractive force between two objects is the van der Waals attraction, which can lead to aggregation of particles.” https://lnkd.in/eNACsghr View in LinkedIn

SOLVENT ACTIONS. “Release of surface hydration water or attached surfactant molecules can yield an additional entropic driving force besides the energy gain through elimination of two high energy surfaces. This would transform the mesocrystal into a single crystal.” https://lnkd.in/eNACsghr View in LinkedIn

MINERAL BRIDGES. “An assembly of mineral bridge connected crystals is in fact also a single crystal. Thus, this concept is the most straightforward one among the mesocrystal formation mechanisms to explain the mutual crystallographic orientation of the nanocrystal.” https://lnkd.in/eNACsghr View in LinkedIn

GEOMETRIC CONSTRAINTS. “The fourth possibility for the formation of a mesocrystal would be a simple geometric argument. When crystalline nanoparticles grow and these nanoparticles are not spherical in shape, simple entropic arguments (known from the Onsager theory of liquid crystallinity) can explain their alignment in a constrained reaction environment upon particle growth.” https://lnkd.in/eNACsghr View in LinkedIn

MINIMAL ENERGY STATES. “The driving force for the geometrical alignment is the minimization of the interface mismatch energy by forming a coherent interface and reducing the exposed surface area while edge sharing is promoted by reduction of the amount of dangling unsaturated bonds along the edge, which have an inherently high chemical energy.” https://lnkd.in/eNACsghr View in LinkedIn

ALCHEMY. “Once a mesocrystal is formed, it can be transformed to a mesocrystal of another mineral system by topotactic conversion under favorable conditions. The term topotaxy (Greek; "topos" = "space" and "taxis" = "in ordered manner") describes all solid state reactions that lead to a material with crystal orientations, which are correlated with crystal orientations in the initial product.” https://lnkd.in/eNACsghr View in LinkedIn

BIOMINERAL MESOCRYSTALS. “An important recent finding is that several Biominerals turned out to be mesocrystals like sea urchin spines, sponge spicules, foraminifera, nacre, calcite prisms in mussel shells,corals, or egg shells, as summarized by Oaki et al. and for calcareous sponge spicules.” https://lnkd.in/eNACsghr View in LinkedIn

GREATER STRENGTH BIOMINERALS. “Compared to a single crystal with cleavage planes, which makes it very brittle, the polycrystal-line mesocrystal structure with soft regions between the singe crystalline nanoparticle building units can make the hybrid material superiour to its constituents.” https://lnkd.in/eNACsghr View in LinkedIn

GREATER THAN THE SUM. “The brittle crystals can add mechanical strength and hardness to the system while the soft polymeric or amorphous phase is deformable and adds elasticity.” https://lnkd.in/eNACsghr View in LinkedIn

THE NUMBERS. “The 3000-fold fracture toughness of nacre was explained by energy dissipation by the polymeric layers.” https://lnkd.in/eNACsghr View in LinkedIn