Image of the week: defects in mesoporous silicas

By Tom Sharp on February 27, 2017

This weeks image comes from a recent Journal of Physics: Condensed Matter paper by Yasuhiro Sakamoto for our special issue on Soft Quasicrystals.

Over the past decade quasicrystals have been reported in many soft-matter systems, thus extending the field of quasicrystals from the more traditional metallic-alloy materials to materials based on supramolecular building blocks such as dendrimers and diblock copolymers, nanoparticles, and colloidal particles.

In this work, Multimodal cage-type mesoporous silicas (MCMSs) with Frank–Kasper type square–triangle tiling are investigated by high resolution transmission electron microscopy (TEM).

HRTEM images of two characteristic defects in square–triangle tilings: (a)–(c) 12-fold wheel arrangement and (d)–(f) stripe bundle arrangement. (a) and (d) Original HRTEM images, (b) and (e) their square–triangle tilings, and (c) and (f) tiling models of the two defects. In (b), defect-mediated (red) and defect-free (green) 12-fold wheel arrangements along with two-mixed arrangements (orange) are shown, where six-fold symmetric hexagons are shown as blue dots. The scale bar is 50 nm. Image taken from J. Phys. Cond. Mat. 29 124002, © IOP Publishing, All Rights Reserved.

Professor Sakamoto identified and characterized three defect structures, and explained them using polyhedral models, producing these stunning images in the process!

Read the full paper here, and find our Special Issue on Soft Quasicrystals here.

This work is licensed under a Creative Commons Attribution 3.0 Unported License