Assembly of Shape-Tunable Colloidal Dimers in a Dielectrophoretic Field

Abstract

The shape of colloid particles plays an important role in directing the structure of their assemblies. Anisotropic colloids can adopt more complex structures than can their spherical counterparts, illustrated here by organosilica dimers fabricated with precise control of particle shape. Dielectrophoretic fields were used to coerce the assembly of 19 uniquely shaped dimers, which allowed direct visualization of the assembly process as well as the structure, symmetry, and long-range order (or lack thereof) of the final state. The various particle shapes resulted in crystalline phases with p6m, cmm, or p2 plane group symmetries, two plastic phases, and a disordered phase. The observations establish a relationship between particle shape and the resulting 2D structures, providing guidance for the design of 2D colloidal crystals.

Stimuli-responsive temporary adhesives: enabling debonding on demand through strategic molecular design

“…266 Similarly, researchers have begun studying the impact of chemical and physical defects in determining mechanical properties. [267][268][269][270][271][272][273][274][275] These efforts should be continued and expanded upon. Future inspiration for adhesive characterization techniques can be adapted from standard industry test methods (e.g., ASTM or TAPPI procedures) commonly applied in other elds of materials characterization.…”

Directional and Reconfigurable Assembly of Metallodielectric Patchy Particles

“…Materials able to reconfigure have long been pursued. They can change their structures and properties in response to environmental stimuli, including pH, temperature, light, etc . − This dynamic feature allows synthetic systems to mimic their biological counterparts ( e.g ., cells and tissues) to evolve, adapt, and eventually serve as smart materials for performing delicate tasks. , In the colloidal regime, external electric/magnetic fields have been commonly employed to obtain dynamic assemblies, which are intrinsically reconfigurable as the field parameters are widely tunable. − For example, the AC electric field has been used to assemble colloidal rods, dimmers, and ellipsoids enabling various frequency-dependent structures ( e.g ., chains, 2D crystals, plastic crystals) and phase transitions. − Accordingly, extending the power of field manipulations to the assembly of patchy particles should induce reconfigurability of the emerged structures. This strategy has previously led to exciting outcomes when Janus particlesessentially particles with one patchare driven by the electric or magnetic fields.…”

Top-Down Heterogeneous Colloidal Engineering Using Capillary Assembly of Liquid Particles

“…3−6 Current strategies for engineering shape anisotropic particles can be loosely categorized as either bottom-up or top-down approaches. 7 Imparting shape anisotropy via bottom-up methods may entail diverging from the free energy minimum configuration throughout colloidal synthesis, 8,9 clustering of spherical particles into higher-order structures, 10−16 and postsynthetically reshaping colloids using stimuli such as temperature, 17−19 surface tension, 20,21 and selective solvation. 22−26 Applications of one or more of these strategies in tandem have resulted in nano-and micron-sized polyhedra, 27,28 patchy particles, 29,30 Janus particles comprising two or more materials, 31−33 and chiral colloids.…”