Hollow self-transformation

Figure 11.7 (a) A scheme for the preparation d) SEM images and (e and f) TEM images of of hollow mesoporous silica spheres via spon- hollow silica spheres. (Reproduced with taneous self-transformation, (b) TEM image of permission from Ref. [44], Copyright 2013, as-made mesostructured silica spheres, (c and American Chemical Society.)... 

The anionic polymerization of masked disilenes proceeds via living anions, and therefore block copolymerization with a conventional vinyl monomer is possible. Recently, interesting hydrophobic block copolymer of PMHS with poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(methacrylic acid) (PMMA) have been prepared (Scheme 11). These polymers can be self-assembled and are transformed into polysilane micelles, shell cross-linked micelles (SCM), and nanometer-sized hollow particles. ... 

Conversions of nanosheets into nanorods have been possible for metal oxides such as ZnO (44). The self-assembled nanosheets arc first prepared by a solution phase hydrothermal synthesis. The reactant solution eontains zine nitrate, hexamethylene tetra-mine and hydrazine, whieh helps in the fonnation of precursor nanosheets in an orderly fashion. At shorter time seales ( 46), nanosheets are formed and after 8 h, hollow microspheres arc formed. The nanosheets arc calcined at 400°C to get ZnO nanorods, as depicted in Figure 7.6. This is an example where one nanostmcture transforms to a completely different morphology. 

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