1. Introduction
In nature, biological organisms produce polymer/inorganic hybrid materials such as bone, teeth, diatoms and shells, which inspired physicists, chemists, and materials scientists to mimic such structures and their properties (Nudelman & Sommerdijk, 2012; Xin et al., 2014). At present, calcium carbonate (CaCO3) are the most abundant crystalline biogenic minerals found in nature. Moreover, CaCO3 have been widely studied owing to their significance in biomineralization processes producing unique organic/inorganic material (Gong et al., 2008; Vilela et al., 2010; Chan, Wu, Li, & Cheung, 2002), biological activities of protein-adhesive properties, cell compatibility, and hard tissue compatibility (Ma, Dong, Fu, Li, & Sun, 2013) and an attractive combination of properties, including opacity, high hardness and density, and low cost. Scientists inspired by the functions of CaCO3in nature have attempted to produce different morphologies and properties of CaCO3 crystals, and propose the formation mechanisms in vitro by mimicking the biomineralization processes (Dmitrovic et al., 2012; Lee, Park, Kwak, & Cho, 2010). So chemistry at ambient temperature plays with organic molecules to open the door to a much wider range of possible polymorphs and morphology. Chitosan as an abundant biopolymer influences the mineralization process of CaCO3is always used as templates or together with soluble addictive (Hosoda & Kato, 2001) for the deposition of CaCO3. By the coexistence of PAA and chitosan membranes the thin island crystals of CaCO3 with aragonite and vaterite forms, which develop into continuous films, were generated (Wada, Suda, Kanamura, & Umegaki, 2004). The work of Neira-Carrillo, Retuert, Martínez, and Arias (2008b) dealt with the effect of the constrained volume given by crosslinked chitosan as a sphere on the in vitro CaCO3 crystallization. Until now, most of the soluble additives which together which chitosan to control the mineralization of CaCO3 were polyanionic or had COOH groups. In the case of calcium carbonate, research has principally concentrated on the influence of anionicadditives as crystal habit modifiers (Ren, Feng, & Bourrat, 2011). However, some studies also focused on the potential role of cationic additives in controlling CaCO3 precipitation (Schenk et al., 2014) and amines were widespread in the biosphere with a very important physiological role. Poly(allylamine hydrochloride) (PAH) was extremely effective in directing the formation of CaCO3 thin films and fibers, where the extent of fiber formation depended on the reaction conditions (Cantaert et al., 2013). Other polyamines such as, PVAm, PAMA, and PEI were further studied the effect on CaCO3 precipitation (Schenk et al., 2014). CaCO3 crystals with different morphologies were synthesized under the regulation of DDAB, [C12mim]Brand the mixed DDAB/[C12mim]Br micelles (Zhao et al., 2011). Various amines such as ethylenediamine, diethylenetriamine (Sugihara et al., 1996), and other polyamines (Gao, Yu, & Guo, 2006) resulted in the formation of disk-like vaterite crystals that have been reported. It was proposed that the major factor for directing the crystal morphology was the adsorption of the amino groups on the CaCO3 crystal surfaces. Moreover, the designed polymer with charged was synthesized to construct LbL systems: negatively charged star-PAA with positively charged chitosan (CHI), and positively charged starPDMAEMA with negatively charged poly (styrene sulfonic acid) sodium salt (PSS), as two different models of confined space for mineralization, where different crystal forms of calcium carbonate were obtained (Yang et al., 2013). The current reports therefore presented no agreement on the effects of positively charged additives on CaCO3precipitation. While a variety of positively charged organic additives have been reported, the co-effect of positively charged soluble organic additives and polycation insoluble substrates was limited. In our work, calcium carbonate crystals were mineralized in the present of cation molecules and chitosan with controlled size and morphology. A study of the co-effect of a range of amine molecules and CS films on CaCO3 precipitation was presented. And the effect of electrostaticfunction on amine monomers on the mineralization of CaCO3 was also investigated. N,N-dimethylaminoethyl methacrylate (DMAEMA), N,N-dimethylethanolamine (DMEA), 2-dimethylaminoethylamine (DMEDA) and N-methIyldiethanolamine (MDEA) were used as crystal modifiers, respectively, because the polymer was harmless to the human body or monomers could be used as drug intermediates. The CaCO3 crystals were obtained on CS films and under the control of DMAEMA, DMEA, DMEDA and MDEA, respectively. While the precipitations without any organic additive, only the single cube-shaped crystals were obtained on CS films. At ambient temperature, cube pile shaped CaCO3 crystals could be only produced by changing the concentration of DMAEMA or DMEA. And the morphology of CaCO3 was divers because of complicated function of DMEDA and CS films. And with the increase of DMEDA concentrations, the change of CaCO3morphologies was regular and controllable. The transformation law of the co-effect of MDEA and CS was similar to that of DMEDA and CS, except the morphology. Our results clearly demonstrated that molecules comprising strong nucleophilicity groups together with CS were capable of exerting potent effects on morphology. In contrast, when only tertiary combined with CS, the effect was little. Positively charged additives are generally considered to be much less active, these results may be useful for further investigation of the cationic mineralization.
1. บทนำ In nature, biological organisms produce polymer/inorganic hybrid materials such as bone, teeth, diatoms and shells, which inspired physicists, chemists, and materials scientists to mimic such structures and their properties (Nudelman & Sommerdijk, 2012; Xin et al., 2014). At present, calcium carbonate (CaCO3) are the most abundant crystalline biogenic minerals found in nature. Moreover, CaCO3 have been widely studied owing to their significance in biomineralization processes producing unique organic/inorganic material (Gong et al., 2008; Vilela et al., 2010; Chan, Wu, Li, & Cheung, 2002), biological activities of protein-adhesive properties, cell compatibility, and hard tissue compatibility (Ma, Dong, Fu, Li, & Sun, 2013) and an attractive combination of properties, including opacity, high hardness and density, and low cost. Scientists inspired by the functions of CaCO3in nature have attempted to produce different morphologies and properties of CaCO3 crystals, and propose the formation mechanisms in vitro by mimicking the biomineralization processes (Dmitrovic et al., 2012; Lee, Park, Kwak, & Cho, 2010). So chemistry at ambient temperature plays with organic molecules to open the door to a much wider range of possible polymorphs and morphology. Chitosan as an abundant biopolymer influences the mineralization process of CaCO3is always used as templates or together with soluble addictive (Hosoda & Kato, 2001) for the deposition of CaCO3. By the coexistence of PAA and chitosan membranes the thin island crystals of CaCO3 with aragonite and vaterite forms, which develop into continuous films, were generated (Wada, Suda, Kanamura, & Umegaki, 2004). The work of Neira-Carrillo, Retuert, Martínez, and Arias (2008b) dealt with the effect of the constrained volume given by crosslinked chitosan as a sphere on the in vitro CaCO3 crystallization. Until now, most of the soluble additives which together which chitosan to control the mineralization of CaCO3 were polyanionic or had COOH groups. In the case of calcium carbonate, research has principally concentrated on the influence of anionicadditives as crystal habit modifiers (Ren, Feng, & Bourrat, 2011). However, some studies also focused on the potential role of cationic additives in controlling CaCO3 precipitation (Schenk et al., 2014) and amines were widespread in the biosphere with a very important physiological role. Poly(allylamine hydrochloride) (PAH) was extremely effective in directing the formation of CaCO3 thin films and fibers, where the extent of fiber formation depended on the reaction conditions (Cantaert et al., 2013). Other polyamines such as, PVAm, PAMA, and PEI were further studied the effect on CaCO3 precipitation (Schenk et al., 2014). CaCO3 crystals with different morphologies were synthesized under the regulation of DDAB, [C12mim]Brand the mixed DDAB/[C12mim]Br micelles (Zhao et al., 2011). Various amines such as ethylenediamine, diethylenetriamine (Sugihara et al., 1996), and other polyamines (Gao, Yu, & Guo, 2006) resulted in the formation of disk-like vaterite crystals that have been reported. It was proposed that the major factor for directing the crystal morphology was the adsorption of the amino groups on the CaCO3 crystal surfaces. Moreover, the designed polymer with charged was synthesized to construct LbL systems: negatively charged star-PAA with positively charged chitosan (CHI), and positively charged starPDMAEMA with negatively charged poly (styrene sulfonic acid) sodium salt (PSS), as two different models of confined space for mineralization, where different crystal forms of calcium carbonate were obtained (Yang et al., 2013). The current reports therefore presented no agreement on the effects of positively charged additives on CaCO3precipitation. While a variety of positively charged organic additives have been reported, the co-effect of positively charged soluble organic additives and polycation insoluble substrates was limited. In our work, calcium carbonate crystals were mineralized in the present of cation molecules and chitosan with controlled size and morphology. A study of the co-effect of a range of amine molecules and CS films on CaCO3 precipitation was presented. And the effect of electrostaticfunction on amine monomers on the mineralization of CaCO3 was also investigated. N,N-dimethylaminoethyl methacrylate (DMAEMA), N,N-dimethylethanolamine (DMEA), 2-dimethylaminoethylamine (DMEDA) and N-methIyldiethanolamine (MDEA) were used as crystal modifiers, respectively, because the polymer was harmless to the human body or monomers could be used as drug intermediates. The CaCO3 crystals were obtained on CS films and under the control of DMAEMA, DMEA, DMEDA and MDEA, respectively. While the precipitations without any organic additive, only the single cube-shaped crystals were obtained on CS films. At ambient temperature, cube pile shaped CaCO3 crystals could be only produced by changing the concentration of DMAEMA or DMEA. And the morphology of CaCO3 was divers because of complicated function of DMEDA and CS films. And with the increase of DMEDA concentrations, the change of CaCO3morphologies was regular and controllable. The transformation law of the co-effect of MDEA and CS was similar to that of DMEDA and CS, except the morphology. Our results clearly demonstrated that molecules comprising strong nucleophilicity groups together with CS were capable of exerting potent effects on morphology. In contrast, when only tertiary combined with CS, the effect was little. Positively charged additives are generally considered to be much less active, these results may be useful for further investigation of the cationic mineralization.
การแปล กรุณารอสักครู่..
