Controlled nanoporous structures of a marine diatom.
We demonstrated chemical etching of a marine diatom shell with 1 N NaOH for controlling the pore size of nanoporous structures of the shell under various conditions. Scanning electron microscopy (SEM) images clearly revealed that the pore size of the diatom shells was regulated in the case of etching at 25 degrees C. In contrast, fluctuations in the etched structures was relatively high even during short periods degradation at 40, 60, and 90 degrees C; therefore, controlled nanoporous structures could not be fabricated. This is the first example of artificial modification of natural diatom shells at the nanoscale although diatom shells have been widely used in industry. In addition, a backbone-like structure was observed during the etching process. The structure was similar to the intermediate structure observed during the primitive stage of the diatom cell growth. Probably, this information is valuable for studying the mechanism of nanoporous structures of diatoms.
Tokyo Tech-Tsinghua University Joint Graduate Program, Tokyo Institute of Technology, Tsinghua University, Beijing 100084, China.
Kazuo
K
Umemura
Xing
X
Liao
Shigeki
S
Mayama
Mohammed
M
Gad
D000818:Animals; D003470:Culture Media / Q000378:metabolism; D017377:Diatoms; D008855:Microscopy, Electron, Scanning; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D013696:Temperature; D013997:Time Factors
D003470:Culture Media