Abstract
In the present paper, attempts have been made to produce transparent silica aerogels with low density and better hydrophobicity by controlled sol–gel route and subsequent atmospheric pressure drying. The hydrogels were prepared by hydrolysis and polycondensation of sodium silicate (Na2SiO3) in the presence of acetic acid catalyzed water followed by several washing steps with water, methanol and hexane, respectively. The surface modification of the wet gel was carried out using a mixture of hexamethyldisilazane (HMDS) in hexane. Since, the sol–gel chemistry provides a straightforward method to control the physical and optical properties of the aerogels, the influence of various sol–gel parameters viz. gel washing time, molar ratios of CH3COOH/Na2SiO3 and HMDS/Na2SiO3 and silylation period on the physical and optical properties of the aerogels have been investigated. The aerogels have been characterized by bulk density, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric and Differential Thermal Analysis (TG-DTA), Atomic Absorption Spectroscopy (AAS), Scanning Electron Microscopy (SEM) studies and Contact angle measurements.
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References
Kocon L, Despetis F, Phalippou J (1998) J Non-Cryst Solids 225:96. doi:10.1016/S0022-3093(98)00322-6
Haranath D, Pajonk GM, Wagh PB, Venkateswara Rao A (1997) Mater Chem Phys 49:129. doi:10.1016/S0254-0584(96)01924-4
Zhou B (1998) J Non-Cryst Solids 225:101. doi:10.1016/S0022-3093(98)00106-9
Smith D, Maskara A, Boes U (1998) J Non-Cryst Solids 225:254. doi:10.1016/S0022-3093(98)00125-2
Carlson G, Lewis D, Mckinley K, Richardson J, Tillostson T (1995) J Non-Cryst Solids 186:372. doi:10.1016/0022-3093(95)00069-0
Schwertfeger F, Frank D, Schmidt M (1928) J Non-Cryst Solids 225:24. doi:10.1016/S0022-3093(98)00102-1
Rao AP, Rao AV, Pajonk GM (2005) J Sol-Gel Sci Technol 36:285. doi:10.1007/s10971-005-4662-1
Prakash SS, Brinker CJ, Hurd AJ, Rao SM (1995) Nature 374:439. doi:10.1038/374439a0
Heimenz PC (1977) Principles of colloid and surface chemistry. Marcel Dekkar, New York
Kistler SS (1932) J Phys Chem 36:52. doi:10.1021/j150331a003
Bikerman JJ (1958) Surface chemistry: theory and applications, 2nd edn. Academic Press, New York, p 343
Venkateswara Rao A, Pajonk GM (2001) J Non-Cryst Solids 285:202. doi:10.1016/S0022-3093(01)00454-9
Einarsrud MA, Nilsen E, Riggaci A, Pajonk GM, Buathier S, Valette D, Durant M, Chevalier B, Nitz P, Ehrburger-Dolle F (2001) J Non-Cryst Solids 285:4. doi:10.1016/S0022-3093(01)00423-9
Reichenauer G (2004) J Non-Cryst Solids 350:3482
Parvathy Rao A, Pajonk GM, Rao AV (2005) J Mater Sci 40:3481. doi:10.1007/s10853-005-2853-3
Kondoh E et al (2000) Jpn J Appl Phys 39(7A, pt.1):3919
Gun’ko VM, Vedamuthu MS, Henderson GL, Blitz JP (2000) J Colloid Interface Sci 228:157. doi:10.1006/jcis.2000.6934
Hering N, Schriber K, Riedel R, Lichtenberger O, Woltersodorf J (2001) Appl Organomental Chem 15:879
Yoldas BE (1984) J Non-Cryst Solids 63:145. doi:10.1016/0022-3093(84)90393-4
Smith CE, Mueller D, Matz P, Reidy R (2006) In: Tsui TY, Joo YC, Volinsky AA, Michaelson L, Lane M (eds) MRS proceeding, vol 914, F04-04
Acknowledgements
The authors are grateful to the Condensed Matter Advisory Committee, Department of Science and Technology (DST), New Delhi, Government of India, for the financial support for this work through a major research project on “Aerogels” (no. SR/S2/CMP-67/2006). Poonam M. Shewale is highly thankful to the Shivaji University Kolhapur for providing ‘Departmental Research Fellowship’. One of the authors Dr. A Parvathy Rao is highly thankful to the DST for the Senior Research Associateship.
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Shewale, P.M., Venkateswara Rao, A., Parvathy Rao, A. et al. Synthesis of transparent silica aerogels with low density and better hydrophobicity by controlled sol–gel route and subsequent atmospheric pressure drying. J Sol-Gel Sci Technol 49, 285–292 (2009). https://doi.org/10.1007/s10971-008-1888-8
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DOI: https://doi.org/10.1007/s10971-008-1888-8