Direct visualization of colloidal rod assembly by confocal microscopy.

Langmuir : the ACS journal of surfaces and colloids (2005-06-01)
Ali Mohraz, Michael J Solomon
ABSTRACT

The development of model materials and image processing methods to directly visualize and quantify colloidal rod assembly by means of confocal laser scanning microscopy (CLSM) is reported. Monodisperse fluorescent colloidal rods are prepared by the uniaxial extensional deformation of sterically stabilized microspheres at elevated temperatures. The particles are stably dispersed in refractive index matching mixed organic solvents for CLSM. An image processing algorithm is developed to detect rod backbones and extract particle centroids and orientation angles from the CLSM image volumes. By means of these methods we quantify the distribution of rod orientation angles in self-assembled structures of rods formed by sedimentation. We find the observations to be consistent with aspect-ratio-dependent jamming and orientational order/disorder transition in the rod sediments.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hexane, anhydrous, 95%
Sigma-Aldrich
Hexane, suitable for HPLC, ≥97.0% (GC)
Sigma-Aldrich
Hexane, puriss. p.a., ACS reagent, reag. Ph. Eur., ≥99% (GC)
Sigma-Aldrich
Hexane, suitable for HPLC, ≥95%
Sigma-Aldrich
Hexane, HPLC Plus, for HPLC, GC, and residue analysis, ≥95%
Sigma-Aldrich
Hexane, ReagentPlus®, ≥99%
Sigma-Aldrich
Hexane, mixture of isomers, anhydrous, ≥99%
Sigma-Aldrich
Hexane, HPLC Plus, for HPLC, GC, and residue analysis, ≥95%
Supelco
Hexane, suitable for HPLC, ≥95%
Sigma-Aldrich
Hexane, mixture of isomers, ACS reagent, ≥98.5%