Using shape for self-assembly

Abstract

A 1980 poem by Alan Mackay outlines his aspiration 'to see what all have seen but think what none have thought': a daunting task, which he accomplished not once, but several times. A 'truly myriadminded, manysided man-a veritable triacontahedron' in the words of his colleagues and friends, Alan Mackay pursued a lifelong interest in the problems of morphogenesis and form, a comprehension of which necessitated him crisscrossing the borders of the inanimate and animate world of soft and hard materials, through the integration of concepts and methods of chemistry, physics, mathematics and biology. In other words, he realized in his time a genuinely interdisciplinary approach to complex problems that still to this day remains beyond much of the academic community. Being invited to contribute a paper on the theme 'beyond crystals', we naturally wondered how Alan Mackay would think about the world of nanoscale self-assembly where so much depends on shape and form.

Rotational and translational diffusion of anisotropic gold nanoparticles in liquid crystals controlled by varying surface anchoring

“…The faceted shape of colloids offers additional director texturing mechanisms, as compared to those with smooth surface curvature [23]. Thus, these literature examples [8][9][10][11][12][13][14][15][16][17][18][19][20][21] show that the interplay of colloidal shape and medium anisotropies of NPs and the chemical functionalization of colloidal surfaces are expected to play key roles in defining their diffusion properties [1], but have not been systematically studied in the past.…”

The memory of surfaces: epitaxial growth on quasi-crystals

“…growth of a structure that has an uncharacteristic crystalline form as a result of assuming the structure of another crystal that has been used as a template self-assembly [4]. In this paper, we consider crystal structures as repositories of information.…”

Self-assembly of micro/nanosystems across scales and interfaces

“…The components inform their short-range spatial coordination, and hence the resulting geometry of the assembly, through shape [19]. Shape anisotropy and shape matching are particularly relevant to design interesting structures.…”

“…We started with wafer-level, inkjet printing (IJP)-based fabrication of SU-8 hemispherical caps which could either host on their flat side hollow cavities of arbitrary geometrical shape or encapsulate thin silicon chips [37]. Hemispheres, easily fabricated by IJP on pedestals, are geometrically well conducive to pair-wise assembly [19]. Additionally, IJP of SU-8 doped with superparamagnetic Fe3O4 nanoparticles within a uniform magnetic field allowed the fabrication of high aspect ratio hemicapsules with anisotropic magnetization profile, which allowed to stir the motion and aggregation of the hemicapsules under external magnetic fields [38].…”