摘要(英) |
In general, nano-particles can be suspended in solution due to Brownian motion. Although van der Waals attractions between particles may lead to aggregation, they are not strong enough to form particle network. Typically, upon the addition of polymers, particle gel can be formed by depletion forces. In this work, we show that silicon carbide (SiC) particles are able to form nanoparticle gel in polar solvent ethylene glycol (EG) by the addition of hydrogen-bond forming surfactants.
When the surfactant dodecylamine (DDA) is added, the SiC/EG system changes from uniform nano-particle suspension to sediment in the presence of clear solution. According to the rheological measurements, the storage modulus is greater than the loss modulus, i.e., G’ > G’’. That is, upon DDA addition, the sediment displays gel-like behavior. As two SiC particles covered with DDA are nearly in contact, hydrogen bonds can be formed between the primary amine head groups (-NH2) and thus result in interparticle attraction. On the basis of the same mechanism, we show that the addition of dodecanic acid, that possesses the same carbon chain length but different head group (-COOH) from DDA, can lead to the formation of nano-particle gel as well.
In addition to the nano-particle gel induced by the addition of hydrogen-bond forming surfactants, we also observe the formation of nano-particle gel in surfactant-free solvent. The examples include SiC nano-particles in decane, ZnO nano-particles in EG, and ZrO2 nano-particles in water or EG. The possible mechanism responsible for particle gel induced by solvent is proposed.
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參考文獻 |
[1] H. J. Möller, Phys. stat. sol., 203, 4, 659–669(2006)
[2] H. J. Möller, Adv. Eng. Mater., 6, 7, 501-513(2004)
[3] Y. J. Sheng, H. K. Tsao, C. N. Yuan, Non-Brownian particle gel ,Applied Physics Letters, 95, 234103 (2009)
[4] 陳宇君,碳化矽粒子於乙二醇中之行為研究探討,國立中央大學,材料科學與工程研究所,碩士論文,民國98年。
[5] 王子瑜、曹恆光,物理雙月刊,廿七卷三期(2005)
[6] B. H. Lavenda, Sci. Amer. 252, 2, 70-85(1985)
[7] 龐寧寧,物理雙月刊,廿八卷一期(2006)
[8] Robert J. Stokes, D. Fennell Evans, Fundamentals of Interfacial Engineering, WILEY-VCH.
[9] J. C. Fariñas, et al., 9, 841-849(1994)
[10] K. Pickrahn, B. Rajaram, A. Mohraz, Relationship between Microstructure, Dynamics, and Rheology in Polymer-Bridging Colloidal Gels, 26(4), 2392-2400(2010)
[11] 林佳吟,以脂肪酸鈉鹽界劑製備水凝膠之行為研究探討,國立中央大學,化學工程與材料工程系,碩士論文,民國98年。
[12] P. Papon, J. Leblond, P. H. E. Meijer, The Physics of Phase Transitions - Concepts and Applications, Springer, 185-188(1999)
[13] D. A. Weitza, V. Prasad, V. Trappe, D. Dinsmore, P. N. Segre, L. Cipelletti, Universal features of the fluid to solid transition for attractive colloidal particles. Faraday Discuss. 123, 1-12(2003)
[14] 刈米孝夫著,界面活性劑的原理與應用,王鳳英編譯,四版,高立圖書,台北縣,1992。
[15] K. Shinoda et al., Colloid surfactants: some physicochemical properties, Academic Press, New York, 1963.
[16] P. Terech and R. G. Weiss, ULow molecular mass gelators of organic liquids and the properties of their gelsU, Chemical Review, No. 97, Vol. 8, 1997.
[17] G. C. Stokes, Trans. Camb. Phil. Soc., 9, 8(1951)
[18] M. T. Arigo, G. H. McKinley, ASME FED., 194, 139-147(1994)
[19] J. F. Richardson, W. N. Zaki, Trans. Inst. Chem. Eng., 32, 35-53(1954)
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