Tectonic arrangement of BaCO3 nanocrystals into helices induced by a racemic block copolymer

Abstract

Morphosynthesis strategies inspired by biomineralization processes gives access to a wide range of fascinating and useful crystalline mesostructures. Biomimetic synthesis of inorganic materials with complex shapes can now be used to control the nucleation, tensorial growth, and alignment of inorganic crystals in a way previously not practicable. Double hydrophilic block copolymers (DHBCs) consisting of a hydrophilic block strongly interacting with inorganic minerals, and a non-interacting hydrophilic block, were recently introduced for the control of mineralization reactions. DHBCs are 'improved versions' of the previously used polyelectrolytes or amphiphiles and are extraordinarily effective in crystallization control. Here, we report on the formation of helices of achiral BaCO(3) nanocrystals in the presence of a racemic DHBC suggesting that a helical alignment can be induced by racemic polymers through selective adsorption on the (110) face of nanocrystals. This mechanism is the key for a better understanding of the self-assembly of chiral organic-inorganic superstructures that don't follow a direct template route.

Rationally Designed Complex, Hierarchical Microarchitectures

“…Strategies inspired by biomineralization have been explored as potential routes to controlling growth and self-assembly from the molecular level via tailored microenvironments, epitaxy and inorganic or organic additives (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). Yet although these have produced some interesting spherical, spiral, leaf-like, and other shapes (25)(26)(27)(28)(29)(30)(31)(32), it is rather disappointing that the appearance of various forms in synthetic systems is often unexpected and the attempts to identify the mechanisms of their formation are generally assessed a posteriori..…”

Anisotropic nanowire growth via a self-confined amorphous template process: A reconsideration on the role of amorphous calcium carbonate

“…S7 in the ESM). According to attachment growth mechanism [21,44], it was suggested that the PAA molecules could selectively adsorb onto and protected the specific crystal planes of these small CaCO 3 particles, and then the other crystal planes with higher surface energy attached to each other to reduce the total surface energy and formed the initial nanowires, thereby providing specifically oriented seeds for the subsequent growth. Eventually, the polymer-adsorbed planes with low energy were left, e. g., {102…”

“…Generally, the formation of anisotropic crystals can be achieved via tuning of the surface energy of crystal faces by changing the temperature and pH, or by adding specific molecules as modifiers [21][22][23][24][25]. An alternative method is to use prefabricated templates with designed shapes and surface functional groups [26][27][28][29].…”

Mesocrystals and Their Related Structures as intermediates between single crystals and polycrystals

“…70) Zhou and O'Brien showed that particle-mediated crystallization leads to the formation of NH 4 TiOF 3 mesocrystals in the presence of a surfactant. 71), 72) As described in Section 1, nanometric crystals are arranged with the same crystallographic orientation in various CaCO 3 -based biominerals 20)22) (Fig. 1).…”