Short communication, Note

Comment of »Theory of the Formation of Colloidal Crystals« by Mirnik

Norio Ise ; Central Laboratory, Rengo Co., Ltd., 186-1-4, Ohhiraki, Fukushima-ku, Osaka 553, Japan

Abstract

Recently Mirnik discussed colloidal crystals1 on the basis of our experimental findings.2 He claimed that the hexagonal structure of one particle surrounded by six others is in reality impossible and what we observed is a not true apparent hexagonal packing. His argument was based on a simple cubic lattice (See Figure 2 in Ref. 1.), which he incorrectly presumed to exist in colloidal dispersions. It should be pointed out that a simple cubic lattice structure has never been observed for colloidal systems. Our micrographic study ,3 X-ray scattering4 and Kossel line analyses5 have established that the crystals belong to a face-centered-cubic (fee) or body-centered cubic (bcc) symmetry, depending on the latex concentration. The (111) plane of an fee structure provides a strictly hexagonal arrangement while the (110) plane of a bcc symmetry shows a slightly deformed hexagonal packing. Thus, his claim that 2Z)exp is apparent interparticle distance is unwarranted, particularly for the fee symmetry, it is actually the center-to- center distance between particles.

Keywords

Hrčak ID:

136757

URI

https://hrcak.srce.hr/136757

Publication date:

1.5.1995.

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