CaCo3 crystallization control by poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer and O-(hydroxy isopropyl) chitosan

Synthesis of vaterite CaCO3 as submicron and nanosized particles using inorganic precursors and sucrose in aqueous medium

“…Their study [39] provides promising results for the elaboration of a biocompatible material for therapeutic applications with encapsulation of bioactive molecules [6,19]. Nanoaggregation is the same mechanism of vaterite formation proposed by Trushina et al [6] Nano-sized grains, as mixtures of vaterite and calcite, have been also reported by Yang et al [5] However, Andreassen [23] claimed that spherical and polycrystalline particles of vaterite precipitated form solution grow by crystal growth of spherulitic type and not by aggregation of nano-sized precursor crystals. This author observed by SEM cauliflower-like particles of vaterite at 40°C and 50°C formed from spherical vaterite particles initially obtained at 25°C.…”

“…Calcium carbonate (CaCO 3 ) exists in six different polymorphs: amorphous calcium carbonate, calcium carbonate hexahydrate, calcium carbonate monohydrate, vaterite, aragonite and calcite, where the thermodynamic stability increases in this sequence [1][2][3][4][5][6][7]. Amorphous calcium carbonate usually contains 15% water, being considered the precursor of more thermodynamically stable CaCO 3 , and aragonite and calcite the most commonly found polymorphs in natural systems [1,[4][5][6][7][8][9]. At normal temperature and pressure conditions (ambient conditions at the surface of earth), the unstable vaterite quickly turns into calcite, which makes their rarity in nature [9].…”

The influence of xanthan on the crystallization of calcium carbonate

“…Spherical hollow, cubic and linear CaCO 3 particles are used as fillers in paper-, plastic-and rubber-making [11]. Therefore, controllable synthesis and properties investigations of CaCO 3 in the presence of additives such as polysaccharides [12][13][14][15][16][17], polypeptide [18,19], proteins [20][21][22][23] and surfactants [24][25][26] have attracted much interest. In our previous study, the influence of O-(hydroxy isopropyl) chitosan (HPCHS) on CaCO 3 crystallization was investigated.…”

“…In our previous study, the influence of O-(hydroxy isopropyl) chitosan (HPCHS) on CaCO 3 crystallization was investigated. It was found that HPCHS inhibits growth of CaCO 3 by adsorption on the newly formed crystal surfaces and edges, which results in stacked rhombohedral crystals with rough surfaces and passivated crystal edges [13].…”

Viscometric Properties of Carboxymethylchitosan Solutions

“…In order to overcome the water-insolubility and extend its applications, a number of water-soluble chitosan derivatives have been studied. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] The investigations indicated that some chitosan derivatives, such as (2-hydroxyl-3-dodecanoxyl) propyl-carboxymethylchitosan (HDP-CMCHS), (2-hydroxypropyl-3-butoxy) propyl-succinylchitosan (HBP-SCCHS), and (2-hydroxyl-3-butoxyl) propyl carboxymethyl-chitosan (HBP-CMCHS) are soluble, have good interfacial activity and form aggregates in concentrated solutions, contributing to their utilization in drug delivery. [12][13][14][15] In addition, HBP-CMCHS and carboxymethylchitosan (CMCHS) have been used in controlling the crystallization of CaCO 3 via the strong electrostatic interaction between the CMCHS -COO − groups and Ca 2+ ions, permitting the dispersion in aqueous solutions of the resulting CaCO 3 particles.…”