Abstract
The in situ determination of the size distribution of dispersed non-spherical nanoparticles is an essential characterization tool for the investigation and use of colloidal suspensions. In this work, we test a size characterization method based on the measurement of the transient behaviour of the birefringence induced in the dispersions by pulsed electric fields. The specific shape of such relaxations depends on the distribution of the rotational diffusion coefficient of the suspended particles. We analyse the measured transient birefringence with three approaches: the stretched-exponential, Watson-Jennings, and multi-exponential methods. These are applied to six different types of rod-like and planar particles: PTFE rods, goethite needles, single- and double-walled carbon nanotubes, sodium montmorillonite particles and gibbsite platelets. The results are compared to electron microscopy and dynamic light scattering measurements. The methods here considered provide good or excellent results in all cases, proving that the analysis of the transient birefringence is a powerful tool to obtain complete size distributions of non-spherical particles in suspension.
Highlights
IntroductionNon-spherical micro and nanoparticles have gained a growing interest because of the number of applications associated to shape (drug delivery, nanosensors, electrorheology, printed electronics, photodetectors,...1–5) as well as their possible use as models with well defined aspect ratios
Non-spherical micro and nanoparticles have gained a growing interest because of the number of applications associated to shape as well as their possible use as models with well defined aspect ratios
Dynamic light scattering is an in situ size characterization technique for nanoparticles in suspension based on the measurement of their translational diffusion coefficient, related to the length L of their major axis as
Summary
Non-spherical micro and nanoparticles have gained a growing interest because of the number of applications associated to shape (drug delivery, nanosensors, electrorheology, printed electronics, photodetectors,...1–5) as well as their possible use as models with well defined aspect ratios. While historically most efforts in size characterization have been directed towards spherical geometries[9], recent works have targeted the size characterization of non-spherical particles. Techniques such as micro-flow imaging, asymmetrical flow field fractionation, dynamic light scattering (DLS), focused beam reflectance measurements or centrifugal separation analysis have been applied to particles with different shapes, there are still many limitations[10,11,12,13,14]. It has been shown that, for these geometries, the contribution of rotational diffusion, not taken into account, can have important effects on the DLS determinations[24,25], and alternative approaches must be proposed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
