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Simulation of mineralization of BaCO3 microstructure by simple CO2 diffusion method

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  • Save American Journal of M aterials Science 2012, 2(4): 105-109 DOI: 10.5923/j.materials.20120204.02 Biomimetic Mineralization of BaCO3 Microstructures By Simple CO2 Diffusion Method B. Sreedhar1, Ch. Satya Vani2, D. Keerthi Devi1, V. Sreeram3, M. V. Basaveswara Rao3,* 1Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology (Council of Scientific and Industrial Research), Hyderabad, Andhra Pradesh, 500607, India 2Department of Chemistry, SR International Institute of Technology, Rampally, Keesara (M ), RR District, Andhra Pradesh, 501301, India 3Department of Chemistry, Krishna University, M achilipatnam, Andhra Pradesh, 521001, India Abstract Bariu m carbonate (BaCO3) microstructures have been synthesized in aqueous solution under ambient condi- tions with PABA (p-amino benzoic acid) and HEEDTA (N-(2 hydroxyethyl) ethylenediamine-N, N’, N’’- triacetic acid) as simp le additives. In this study we demonstrate that the integration of both the additives, PABA and HEEDTA under different e xperimental conditions, such as crystallization sites and pH will e xtend the possibilities for controlling the shape and size on microstructures of the inorganic crystals by means of a slow CO2 simple d iffusion route. The influence of variation of pH condition with two different additives on the particle size and morphology was investigated. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray powder diffracto metry were used to characterize the products. The results indicate that bunch like dendrit ic and limpet teeth shaped, BaCO3 microstructures were obtained. Increasing pH led to the separation of rods from the co mplex structures. Keywords Bariu m Carbonate, P-Amino Benzo ic Acid, N-(2hydro xyethyl) Ethylenediamine-N, N’, N’’- Triacetic Acid and Bio mineralizat ion 1. Introduction Highly ordered co mplex structures have been studied extensively due to their unique nature and fantastic properties different fro m those of the mono morph structures[1]. For this, biomimet ic synthesis of inorganic materials with complex and heirarch ial structures, templates or organic additives with comp lex functionalizat ion patterns are used to control the nucleation growth and alignment of inorganic cry s tals . Researchers are increasingly concerned with the synthesis of advanced materials with enhanced properties. The use of inorganic-organic interface for the mo rphosynthesis of inorganic materials is an emerg ing soft chemical route[2]. The mo lecular interactions between inorganic - organic interface seem to control nucleation and growth which often stabilizing new mod ificat ions and morpho log ies[3]. Carbon ate minerals like CaCO3, BaCO3, and SrCO3, were intensively studied as a model co mpound for bio mimet ic mineralization[4]. BaCO3 is having close resemblance with the aragonite type mineral with many industrial applications in the ceramic and glass industries as well as its use as a precursor fo r mag net ic ferrit es and /o r ferro elect ric materials [5]. Bariu m carbonate (BaCO3) is also used as aprecursor for producing superconductor and ceramic materials[6] and other important applicat ions in optical glass and electric condensers[7]. Various mo rphologies such as helical BaCO3 fibers[8,9] candy-like, needle like or olivary like[10], nanofibers and rod like structures[11] in the presence of different additives are reported. In literature d ifferent bio mimet ic approaches to control the morphology of carbonate systems using a variety of additives/templates, such as Lang muir films[12-14], ultrathin o rganic films[15], self assembled monolayers[16-18], varied soluble additives like synthetic peptides[19], dendrimers[20,21], n icotinic acid[22], H5hpdta, H3heidi[23], PA BA[24] and co mmon poly mers[25,26] have been described. Here in, we present a study, on the biomimet ic synthesis of BaCO3 crystals by using two different organic additives, namely PABA and HEEDTA with simple CO2 gas slow diffusion technique to prepare dendritic and limpet teeth shaped BaCO3 structures, respectively in aqueous solution. However, to the best of our knowledge, limpet–teeth like Ba CO3 structures have not been reported till now. 2. Experimental * Corresponding author: (M.V. Basaveswara Rao) Published online at Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved 2.1. Materials and instruments Para-aminobenzoicacid (C7H7O2N), N-(2hydroxyethyl) ethylenediamine-N, N’, N’’-triaceticacid (C10H18O7N2), 106 B. Sreedhar et al.: Biomimetic M ineralization of BaCO3 M icrostructures By Simple CO2 Diffusion M ethod ammon iu m carbonate (NH4)2CO3, sodium hydroxide (NaOH) and barium chloride (BaCl2) were o f analytical grade and used without further purification. Double distilled water was used in all e xpe riments. 2.2. Materials X-ray diffraction measurements of the bariu m carbonate hierarchial structures were recorded using a Rigaku diffractometer (Cu rad iation, λ = 0.1546 n m) running at 40 kV and 40 mA (Tokyo, Japan). FT-IR spectra of BaCO3 structures were recorded with a Thermo Nicolet Nexus (Washington, USA) 670 spectrophotometer. The crystals were collected on a round cover glass (1.2 cm), washed with deionized water and dried in a desiccator at room temperature. The cover glass was then mounted on a SEM stub and coated with gold for SEM analysis. teeth morphology of complex h ierarch ical structures. All of these complex microstructures were co mposed of microrods with d iameters in the range of 1µm – 1.5µm. In co mparison with Figures 1 (a)-(c), the pattern in Figures 2 a-2c has three changes. One is that two new diffraction peaks, (041) and (202) faces appear, and the second is that the relative intensity of (112), (200) planes are decreased at initial pH 3 and raised pH 10. The third main d ifference is the resolution of (021) as separate peak next to (111). This suggests that PABA and HEEDTA have different influence on the crystal growth of BaCO3 which also can be interpreted by the fact that the two organic molecules can adsorb onto certain crystal faces BaCO3 crystals and influence the crystal growth p ro cess . 2.3. Synthesis of BaCO3 Crystals A typical procedure for preparation of crystalline BaCO3 crystals was carried out as follows: 2.5 mmo l BaCl2, 0.1 mmo l PABA/HEEDTA were dissolved in 20 mL H2O, prepared in a glass bottle and stirred continuously for co mplete dissolution. Then the pH of the solution was ad justed to 7.0 and 10.0 by using dilute NaOH. After that the prepared solution was then covered with parafilm which was punched with three needle holes and placed in larger desiccator containing crushed ammoniu m carbonate at the bottom. After 24hr crystallizat ion, the parafilm was removed and the white precipitate deposited on the glass bottle rinsed with distilled water and ethanol and allowed to dry at roo mtemperature for further crystallization. 3. Results 3.1. Structural Characterizati on of BaCO3 Crystals The crystal structures and the phase purity of the materials were determined by X-ray diffract ion (XRD). XRD patterns of the as-prepared dendritic and limpet teeth shaped BaCO3 microstructures at two different pH conditions – 7 and 10 are presented in Figures 1 and 2. All the observed diffraction peaks of the products can be attributed to pure orthorhombic BaCO3 crystals (JCPDS card nu mber: 71-2394). In Figure 1, the pattern of BaCO3 crystals obtained in PABA solution displays the following diffraction peaks with (hkl) indices (110), (020), (111), (021), (002), (112), (200), (220), (221) (041), (202), (132), and (113). In Figure 2, the pattern of BaCO3 crystals obtained in HEEDTA solution displays the following diffraction peaks with (hkl) indices (110), (020), (111), (021), (002), (112), (200), (220), (221), (132), and (113), of pure orthorho mbic witherite phase. It may also be seen that the peak at (111) is the strongest, suggesting that BaCO3 crystals obtained with PABA and HEEDTA aqueous solutions were well oriented and grew main ly along the crystallographic C-axis. This result was also maintained by SEM observation, which exhibited the dendrite and limpet Figure 1. XRD pattern of BaCO3 in the presence of PABA1 (a) pH 3.0, (b) pH 7.0 and (c) pH 10.0. Figure 2.XRD pattern of BaCO3 in the presence of HEEDT A 2 (a) pH 3.0; (b) pH 7.0, and (c) pH 10.0 3.2. Infl uence of Additi ves on the Morphol ogy of BaCO3 Significant changes in the morphologies were observed when the pH of the reaction conditions were varied – 7 and 10. Figure 3 and 4 show the SEM images of BaCO3 structures obtained before and after adding the addit ives PABA and HEEDTA, respectively at init ial pH(3.0) and rised pH(7.0 and 10.0) conditions. As can be seen From Figure 3a, and 4a, BaCO3 microrods are obtained in the absence of additive, while in the presence of PA BA at starting pH 3.0(without rising with NaOH), bunch like dendritic structures were observed (Figure 3b). Fro m the magnified image American Journal of M aterials Science 2012, 2(4): 105-109 107 it can be clearly seen that the branch like product are built up of much smaller size subunits shown as inset in Figure 3b. No changes were observed in the morphology when the pH of the react ion mixture was increased to 7, except an increase in the length of the dendritic structures as shown in Figure 3c. On further increasing the pH to 10.0, the bunch like dendrit ic structures are separated and become almost twin shaped rods. As can be seen, at all the three different pH conditions, similar morphological changes with variat ion in the length of the dendritic structures were identified. Figure 4 shows the SEM images of BaCO3 structures in the presence of the additive HEEDTA. Significant changes in the morphology was observed with this additive and the shape of BaCO3 structures changed fro m rods to limpet teeth which is isostructural with the mineral aragonite, with sizes ranging fro m several micro meters to several tens of micro meters. At initial pH 3.0 mo re branches with long rods and sharp tips are observed. At neutral p H, short sized rods with less number of branches that are dispersed are seen. At pH 10.0, morphology of the BaCO3 structures appears similar to that observed at initial p H 3. Moreover, the tips of the rods are not too sharp as seen in initial pH 3.0. So it can be concluded that, even though the morphology at different pH remain same, variation in the branching and size of the subunits is observed in the controlled experiments through the slow gas diffusion method. Fro m the above morphology evolvement, we could clearly see the important role of PA BA and HEEDTA under varied conditions during the crystal formation and growth process. The growth process of the branch like dendrites and limpet-teeth like mo rphology was carefully followed by pH-dependent experiments. SEM images of the products with d ifferent reaction t ime showed an obvious growth process fro m rods to bunch like dendrite units with PA BA and rods to limpet teeth with HEEDTA. Figure 3 and 4 summarizes all major steps and changes involved in the formation of the BaCO3 co mplex structures. However, it has to be pointed out that the exact growth mechanism is still unknown, although some exp lanation was given in the literature based on the role of intrinsic electric fields which direct the growth of dipole crystals[27-29]. 3.3. FT-IR Analysis To identify the growth mechanism and the effect of PA BA and HEEDTA on BaCO3 microstructures, the sample was analyzed by FT-IR spectroscopy. The IR bands at 1445 c m-1 (Figure 5b), and 1435 cm-1 (Figure 5c) correspond to the asymmetric stretching mode of C-O bond, while the weak band at 1059 cm-1 (Figure 5b, c) is attributed to the symmetric C-O stretching vibration. The weak bands at 1165 and 1059 cm-1 are C-H in-p lane bending vibrations and the small peaks between 1500 cm-1 to 1400 cm-1 are C-C stretching vibrations in aro mat ic ring (Figure 5b). The extra peaks in Figure 5b and 5c are attributed to the functional groups (-COOH, NH2, OH) that are present in the addit ives. In comparison with Figures 5b, the C-O stretching vibration peak around 1435 cm-1 in Figure 5c, shifts to lower frequency by 10 cm-1 (1445 cm-1), suggesting that PABA and HEEDTA have different influence of BaCO3. Th is is probably due to the fact that the two organic molecu les can adsorb onto the different planes of BaCO3 nuclei and influence the mode of crystal growth, resulting in litt le change of microstructure. Figure 3. SEM images of BaCO3 in the presence of PABA at varied pH conditions (a) absence of PABA, (b) initial pH 3.0, (c) pH 7.0, and (d) pH 10.0. Figure 4. SEM images of BaCO3 in the presence of HEEDT Aat varied pH conditions (a) absence of HEEDTA, (b) initialpH3.0, (c) pH7.0, and (d) pH 10.0. Figure 5. FT-IR of BaCO3 microstructures nucleated (a) in the absence of an additive, (b) presence of PABA, and (c) presence of HEEDTA. 108 B. Sreedhar et al.: Biomimetic M ineralization of BaCO3 M icrostructures By Simple CO2 Diffusion M ethod 4. Discussion On the basis of SEM observation, the growth mechanism for the generation of BaCO3 complex structures can be described as rod to dendritic like structures and rod to limpet teeth shaped progression for PA BA and HEEDTA, respectively. The first stage is the nucleation process that is the initial react ion between Ba2+ and amino/ carbo xylic anions in PABA and hydroxyl/carbo xy lic anions in HEEDTA, which generates the BaCO3 nuclei. The second stage is the formation of BaCO3 rods via orientation growth along the crystallographic c-a xis, as demonstrated by XRD. The third stage involves the format ion of branches at the ends of the primary rod in PABA whereas with HEEDTA all over the branches on the primary rod leading to the formation of bunch like dendritic structures or limpet teeth like BaCO3 microstructures. The results above show that PABA promotes the formation of branch like dendritic structures while HEEDTA favors the formation of limpet teeth like BaCO3 crystals. So it can be presumed that the amino and/or carbo xylic anions in PABA and hydro xyl and/or carbo xy l an ions in HEEDTA control the format ion of microstructures by adsorbing onto certain facets of BaCO3 crystals. 5. Conclusions Different morphologies of BaCO3 co mplex structures were controlled by the cooperation of the PABA and HEEDTA additives by means of a slo w CO2 simp le d iffusion technique. It is noticeable that the pH variation with both the different organic additives has remarkable effect on the morphology. In this system pH and additive is the key factor for the bio mineralisation research and development of new materials which could find various applications. [6] L. Chen, Y. Shen, A. Xie, J. Zhu, Z. Wu, and L. Yang., 2007, Nanosized barium carbonate particles stabilized by cetyltrimethylammonium bromide at the water/hexamethylene interface, Cryst. Res. Technol. 42(9), 886 – 889. [7] D. Jin, X. Yu, L. Yue, and Ping Sun., 2009, Synthesis of BaCO3 with Different M orphologies Using Amphiphilic PS–PAA Copolymer as M edium Inorganic M aterials, 45( 2), 168–172. [8] J. H. Zhu, S. H. Yu, A. W. Xu, and H. Colfen., 2009, The biomimetic mineralization of double-stranded and cylindrical helical BaCO3 nanofibres, Chem. Commun. 1106-1108. [9] S. H. Yu, H. Colfen, H. K. Tauer, and M . Antonietti., 2005, Tectonic arrangement of BaCO3 nanocrystals into helices induced by a racemic block copolymer, Nat. M ater. 4, 51-55. [10] T. Wang, J. M itchell, H. Borner, H. Colfen and M . Antonietti., 2010, BaCO3 mesocrystals: new morphologies using peptide–polymer conjugates as crystallization modifiers, Phys. Chem. Chem. Phys. 12, 11984–11992. [11] T. X. Wang, A. W. Xu, and H. Colfen., 2006, Formation of Self-Organized Dynamic Structure Patterns of Barium Carbonate Crystals in Polymer-Controlled Crystallization, Angew. Chem. Int. Ed. 45(27), 4451-4455. [12] S. M ann, B. R. Heywood, S. Rajam, and S. J. D. Birchal., Controlled crystallization of CaCO3 under stearic acid monolayers, Nature 1988, 334, 692-695. [13] D. J. Ahn, A. Berman, and D. Charych., 1996, Probing the Dynamics of Template-Directed Calcite Crystallization with in Situ FTIR, J. Phys. Chem. 100(30), 12455-12461. [14] A. L. Litvin, S. Valiyaveettil, D. L. Kaplan, and S. M ann., 1997, Template-directed synthesis of aragonite under supramolecular hydrogen-bonded langmuir monolayers, Adv. M ater. 9(2), 124-127. [15] D. D. Archibald, S. B. Qadri, and B. P. Gaber., 1996, M odified Calcite Deposition Due to Ultrathin Organic Films on Silicon Substrates, Langmuir, 12(2), 538-546. REFERENCES [1] X. X. Xu, X. Wang, A. Nisar, X. Liang, J. Zhuang. S. Hu, and Y. Zhuang., 2008, Combinatorial Hierarchically Ordered 2D Architectures Self-assembled from Nanocrystal Building Blocks, Adv. M ater. 20(19), 3702-3708. [2] S. M ann, D. D. Archibald, J. M . Didymus, B. R. Heywood, F. C. M eldrum and V. J. Wade., 1992, M RS Bull. 32. [3] S. M ann, D. D. Archibald, and J. M . Didymus, T. Douglas, B. R. Heywood, F.C. M eldrum, and N. J. Reeves., 1993, Crystallization at Inorganic-organic Interfaces: Biominerals and Biomimetic Synthesis, Science 261, 1286-1292. [4] W. Li, S. Sun, Q. Yu, and P. Wu., 2010, Controlling the M orphology of BaCO3 Aggregates by Carboxymethyl Cellulose through Polymer Induced Needle-Stacking Self-Assembly, Cryst. Growth Des. 10(6), 2685-2692. [16] J. Kuther, G. Nelles, R. Seshadri, M . Schaub, H.J. Butt, and W. Tremel., 1998, Templated Crystallisation of Calcium and Strontium Carbonates on Centred Rectangular Self-Assembled M onolayer Substrates, Chem. Eur. J. 4(9), 1834-1842. [17] J. Aizenberg, A. J. Black, and G. M . Whitesides., 1999, Control o f crystal nucleation by patterned self-assembled monolayers, Nature. 398, 495-498. [18] J. Aizenberg, A. J. Black, and G. M . Whitesides., 1999, Oriented Growth of Calcite Controlled by Self-Assembled M onolayers of Functionalized Alkanethiols Supported on Gold and Silver, J. Am. Chem. Soc. 121(18), 4500-4509. [19] D. B. DeOliveira, and R. A. Lauren., 1997, Control of Calcite Crystal M orphology by a Peptide Designed To Bind to a Specific Surface, J. Am. Chem. Soc. 119(44), 10627-10631. [20] K. Naka, Y. Tanaka, Y. Chujo, and Y. Ito., 1999, The effect of an anionic starburst dendrimer on the crystallization of CaCO3 in aqueous solution, Chem. Commun. 1931-1932. [5] A. Zelati, A. Amirabadizadeh, and A. Kompany., 2011, [21] N. Naka. 2003, Top. Curr. Chem. 141, 228. Preparation and Characterization of Barium Carbonate Na- noparticles, International Journal of Chemical Engineering [22] C. Satyavani, K. Balakrishna, C. Rambabu, M . Saratchandra and Applications, 2(4), 299-303. Babu., 2010, Influence of Vitamin B3 on M orphosynthesis of American Journal of M aterials Science 2012, 2(4): 105-109 109 CaCO3, BaCO3 and SrCO3 M icro and Nano Structures, J. M etallurgy and M aterials Science. 52(4), 351-356. [23] M . Saratchandra Babu, C. E. Anson and A. K. Powell., 2006, M odelling CaCO3 Biomineralisation process, J. of Inorg. Biochem. 100, 1128. [24] M . Saratchandra Babu, C. Satyavani, C. Rambabu and K. Sethuram., 2010, Biomimetic Growth of flower like calcite morphology, J. M at. Sci. 7, 55. [25] S. H. Yu, H. Colfen, A. W. Xu, and W. F. Dong., 2004, Complex Spherical BaCO3 Superstructures Self-Assembled by a Facile M ineralization Process under Control of Simple Polyelectrolytes, Cryst. Growth Des. 4(1), 33-37. [26] J. T. Han, X. Xu, D. H. Kim, and K. Cho., 2005, Biomimetic Fabrication of Vaterite Film from Amorphous Calcium Car- bonate on Polymer M elt:  Effect of Polymer Chain M obility and Functionality, Chem.M ater. 17(1), 136-141. [27] R. Kniep, and S. Busch., 1996, Biomimetic Growth and Self-Assembly of Fluorapatite Aggregates by Diffusion into Denatured Collagen M atrices, Angew. Chem. Int. Ed. Engl. 35(22), 2624-2626. [28] S. Busch, H. Dolhaine, A. DuChesne, S. Heinz, O. Hochrein, F.Laeri, O.Podebrad,U.Vietze, T.Weiland, and R.Kniep.,1999, Biomimetic M orphogenesis of Fluorapatite-Gelatin Composites: Fractal Growth, the Question of Intrinsic Electric Fields, Core/Shell Assemblies, Hollow Spheres and Reorganization of Denatured Collagen, Eur. J. Inorg. Chem. 1999(10), 1643-1653. [29] H. Colfen and L. Qi., 2001, Prog Colloid Polym. Sci. 11, 200.

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