Page 283 - Book Hosokawa Nanoparticle Technology Handbook
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FUNDAMENTALS                                           CH. 4 CONTROL OF NANOSTRUCTURE OF MATERIALS












































                  Figure 4.6.12
                  The fine particle-wiring array prepared by drying patterning (a f): The same sample showing different rainbow structural
                  colors depending upon the direction of observation. (A~E): Microstructure of the fine particle-wiring array.

                  other than fcc (hcp) by the particle self-assembling  method having the advantages of both processes has
                  phenomena from the colloid solution, which indi-  been developed in order to realize the preparation of
                  cates the great potential of the self-assembling  particle self-assembled agglomerate pattering [20]
                  process.                                       and the preparation and patterning of spherical parti-
                                                                 cle agglomerates [21].
                  (a) Two-solution self-assembly method
                                                                 (b) Preparation of particle self-assembled collectives
                  Liquid-phase patterning and drying patterning have
                  advantages and disadvantages. In the liquid phase,  pattering by two-solution method
                  there is the advantage of utilization of the electrostatic  After making a self-assembled monolayer with the
                  interaction and reactions between the particles and the  patterning of hydrophobic and hydrophilic regions
                  board against the disadvantage of less driving force  on the silicon board, methanol solution with dis-
                  for the closest packing of particles.          persed particles is dropped on it (Fig. 4.6.13). Then
                    In the process of the drying solution, the meniscus  the solution is repelled from the hydrophobic region
                  force generated at the contraction of the colloid solu-  and patterned along with the hydrophilic region.
                  tion and drying of solvent between the particles can  After that, it is soaked in decalin solution, which is
                  be used as the driving force for the closest packing of  barely soluble to methanol. With gradual solution of
                  particles, while there is the disadvantage that chemi-  methanol in decalin, the area of methanol including
                  cal reactions are hardly made use of because of the  the particles shrinks and the particles become closer
                  dynamic process. For these reasons, the two-solution  to each other.

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