Colloidal Crystal Wires

M. Tymczenko; L. F. Marsal; T. Trifonov; I. Rodriguez; F. Ramiro-Manzano; J. Pallares; A. Rodriguez; R. Alcubilla; F. Meseguer

doi:10.1002/adma.200701526

Research · Publication & note

Colloidal Crystal Wires

Advanced Materials · Journal article · 18 June 2008

Michael Tymczenko, Lluis F. Marsal, Trifon Trifonov, Isabelle Rodriguez, Fernando Ramiro-Manzano, Josep Pallares, Angel Rodriguez, Ramon Alcubilla and Francisco Meseguer

Advanced Materials

Volume 20

Issue 12

Pages 2315–2318

2008

Abstract

Several configurations of colloidal wires are obtained by infiltration of charge-stabilized polystyrene spheres into cylindrical pores of a silicon membrane. As channel dimensions are comparable to those of particles, wirelike arrangements are governed by the ratio between the pore diameter and the particle diameter. Also, Coulomb repulsion between particles plays a very important role in the particle ordering.

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© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The subscription Version of Record is not hosted here. Figures from the article are shown on an author’s personal website with full citation and remain subject to Wiley’s copyright and contributor-reuse terms.

Figures

Scheme showing latex-sphere infiltration, PDMS infiltration and template removal to obtain colloidal crystal wires

Figure 1. Fabrication sequence: infiltration of latex spheres into the silicon pores, infiltration with PDMS and removal of the silicon template to release the colloidal crystal wires.

From M. Tymczenko et al., Advanced Materials 20, 2315–2318 (2008), DOI 10.1002/adma.200701526. © Wiley-VCH.

Three SEM panels showing polystyrene spheres inside silicon pores, a side view after PDMS infiltration and released colloidal crystal wires

Figure 2. Representative wire-like colloidal arrangements obtained for different ratios between pore diameter and particle diameter.

From M. Tymczenko et al., Advanced Materials 20, 2315–2318 (2008), DOI 10.1002/adma.200701526. © Wiley-VCH.

Composite SEM figure comparing colloidal crystal wire arrangements for confinement ratios D from 1.3 to 2.9 with corresponding sphere-packing models

Figure 3. Colloidal-wire configurations comparing experimental particle ordering with the corresponding structural models.

Research fields

Bottom-up

Polystyrene colloids infiltrate cylindrical pores in a macroporous silicon membrane and organise under radial confinement. Removing or retaining the surrounding matrix yields wire-like particle assemblies whose helicity and coordination depend on the pore-to-particle diameter ratio.

Simulations & fits

A confined-sphere interaction model includes geometry and electrostatic repulsion to reproduce non-close-packed zigzags and helical sequences. Varying the effective confinement ratio connects individual observed wires with the corresponding packing family.

Characterization

Cross-sectional and released-wire SEM images expose particle order inside the pores and along isolated strands. The comparison reveals structures hidden from a top view and tests whether the same sequence persists after the silicon template is removed.

RESEARCH TOPICS

MaterialsPolystyrene spheres are infiltrated into cylindrical pores of a porous-silicon membrane, producing true two-dimensionally confined colloidal wires rather than particles resting in open surface channels. The governing parameter D is the pore diameter divided by sphere diameter. Figure 3 pairs SEM images with packing models and shows how changing D selects single files, zigzags, helices and multi-strand structures; Figure 2 confirms infiltration through the membrane. These micrometre-scale assemblies provide direct experimental counterparts to hard-sphere packing predictions and a route to chiral or waveguiding colloidal fibres.