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FUNDAMENTALS                             CH. 1 BASIC PROPERTIES AND MEASURING METHODS OF NANOPARTICLES
                  substrate [23, 24]. It can be found that the contact  1.6 Specific surface area and pore
                  angles of all liquid metals decrease at less than 40nm
                  and a remarkable decrease of the contact angles is  Nanoparticles have a large specific surface area, and
                  observed when particle radius is less than 10nm.
                                                                 hence their properties are dominated by surfaces rather
                                                                 than bulk. The specific surface area is often used as a
                                   References                    basic unit for the particle properties of nanoparticles.
                                                                 In this section, methodologies and things to be consid-
                   [1] M. Takagi: J. Phys. Soc. Jpn., 9, 359–363 (1954).  ered for analyzing particle size from specific surface
                   [2] F.O. Jones, K.O.  Wood:  Brit J. Appl. Phys.,  15,  area will be discussed. The first half of this section will
                      185–187 (1964).                            describe requirements for measuring particle size dis-
                   [3] N.T. Gladkich, R. Niedermayer and K. Spiegel: Phys.  tribution from specific surface area. In the second half,
                                                                 pore size distribution will be reviewed as an applica-
                      Stat. Sol., 15, 181–192 (1966).
                                                                 tion of the measurement of specific surface area.
                   [4] C.R.M. Wronski: Brit. J. Appl. Phys., 18, 1731–1737
                                                                  It is important to access thoroughly the influence of
                      (1957).
                                                                 particle shapes and particle size distribution for meas-
                   [5] B.T. Boiko, A.T. Pugachev and V.M. Bratsykhin: Sov.
                                                                 uring particle size from specific surface area. For this
                      Phys. Solid State, 10, 2832–2834 (1969).   reason, using electron microscopic observations or
                   [6] J.F. Pocza, A. Barna and P.B. Barna: J. Vac. Sci. Tech.,  other particle size measurements are preferable in
                      6, 472–475 (1969).                         combination with the measurement of specific sur-
                   [7] M. Blackman, J.R. Sambles: Nature, 226, 938 (2970).  face area. Comprehensive analysis for these measure-
                   [8] M.J. Stowell, T.J. Law and J. Smart: Proc. Roy. Soc.  ments would enable to estimate reasonable and
                      London A, 318, 231–241 (1970).             meaningful particle size.
                                                                  The relationship between specific surface area and
                   [9] J.R. Sambles:  Proc. Roy. Soc. London A,  324,
                                                                 particle size is described here with an ideal particle
                      339–351 (1970).
                                                                 model. As shown in Fig. 1.6.1, ideal size reduction
                  [10] C.J. Coombes:  J. Phys. F: Metal Phys., 2, 441–449
                                                                 where a dense cube, 1 cm on a side, is divided into
                      (1972).
                                                                 cubes, l cm on a side, is supposed. The surface area of
                  [11] M. Bkackman, S.J. Peppiatt and J.R. Sambles: Nature  each divided cube is given as 6·l and the number of
                                                                                           2
                      Phys. Sci., 239, 61–62 (1972).             divided cubes is given as 1/l . Therefore, the total sur-
                                                                                       3
                  [12] R.P. Berman, A.E. Curzon: Can. J. Phys., 52, 923–929  face area of all the divided cubes can be expressed as
                                                                        2
                                                                    3
                      (1974).                                    (1/l )·( 6l ), thus 6/l. Supposing the true density of a
                  [13] S.J. Peppiat, J.R. Sambles: Proc. R. Soc. Lond. A, 345,  particle  , specific surface area S is given by
                      387–399 (1975).

                                                                                         l
                                                                                  S   6(  )            (1.6.1)
                  [14] S.J. Peppiatt: Proc. R. Soc. London A, 345, 401–412
                      (1975).                                    In contrast, supposing that the powder is composed of
                  [15] P. Buggst, J.P. Boreld: Phys. Rev. A, 13, 2287–2298  uniform cubic particles, the particle size can be given
                      (1976).
                  [16] G.L. Allen, W.W. Gile and W.A. Jesser: Acta Metall.,
                      28, 1695–1701 (1980).
                  [17] V.P. Skipov,  V.P. Koverda and  V.N. Skokov:  Phys.
                      State. Sol., 66, 109–118 (1981).
                  [18] M.S. Rahman: Micron, 13, 273–274 (1982).
                  [19] G.L. Allen, R.A. Bayles, W.W. Gile and W.A. Jesser:
                      Thin Solid Films, 144, 297–308 (1986).                                          S=6/d•l
                  [20] H. Saka. Y. Nishikawa and T. Imura: Phil, Mag. A, 57,
                                                                         1 × 1 × 1 cm 3
                      895–906 (1988).
                  [21] N.T.  Gladkikh, L.K. Grigoreva, S.V. Dukarov,
                      V.E. Zilbervarg,  V.I. Larin, E.L. Nagaev and S.P.
                      Chizhik: Sov. Phys. Solid State, 31, 728–732 (1989).
                  [22] I.D. Morokhov, S.P. Chizhik, N.T. Gladkikh,
                      L.K. Grigoreva, S.V. Stepanova: Izv. Akad. Nauk SSSR
                      Metall., 6, 159–161 (1979).                                                area : 6 • l 2
                                                                                      1/l
                  [23] N.T. Gladkikh: Fiz. Khim. Obrabot. Mater., 2, 96–102                      number : (1/l) 3
                                                                                     division
                      (1979).
                  [24] S.P. Chizhik: Izv. Akad. Nauk SSSR Metall., 4, 73–79  Figure 1.6.1
                      (1981).                                    Relationship between particle size and specific surface area.
                  20
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