Development and Evaluation of Polyether Ether Ketone (PEEK) Capillary for Electrospray

[Image: see text] With the rapid development of nanotechnology, there is urgent need of characterizing techniques; especially determining the particle size distribution directly from solution. Dynamic light scattering is often used but presence of a small number of aggregates can greatly influence the size distribution. Electrospray scanning mobility particle sizer (ES–SMPS) is rapidly emerging as an alternative method in colloidal science. However, a major limitation is the use of silica-coated capillaries, which are negatively charged at pH > 3, and therefore making its use difficult for positively charged nanoparticles. In this work, we have developed the polyether ether ketone (PEEK) capillary for ES–SMPS, which removes this limitation because it carries no charge. We have shown that the new capillary not only produced equally good particle size distributions for negatively charged particles (SiO(2), Au, and latex) as obtained with silica capillaries, but also precise particle size distributions for positively charged particles (TiO(2)). Moreover, the PEEK capillaries are much cheaper than the silica capillaries. Thus, the results shown in this paper strengthen the development of the ES–SMPS method as a versatile method for determining the particle size distributions of colloidal sols directly from solution.