Polyelectrolyte assisted charge titration spectrometry: Applications to latex and oxide nanoparticles

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• 作者：F. Mousseau^a ; ^{fanny.mousseau@univ-paris-diderot.fr" class="auth_mail" title="E-mail the corresponding author} ; L. Vitorazi^a ; L. Herrmann^a ; S. Mornet^b ; J.-F. Berret^a ; ^{jean-francois.berret@univ-paris-diderot.fr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Charge density ; Nanoparticles ; Light scattering ; Polyelectrolyte complex
• 刊名：Journal of Colloid and Interface Science
• 出版年：2016
• 出版时间：1 August 2016
• 年：2016
• 卷：475
• 期：Complete
• 页码：36-45
• 全文大小：1792 K

文摘

The electrostatic charge density of particles is of paramount importance for the control of the dispersion stability. Conventional methods use potentiometric, conductometric or turbidity titration but require large amount of samples. Here we report a simple and cost-effective method called polyelectrolyte assisted charge titration spectrometry or PACTS. The technique takes advantage of the propensity of oppositely charged polymers and particles to assemble upon mixing, leading to aggregation or phase separation. The mixed dispersions exhibit a maximum in light scattering as a function of the volumetric ratio X$X$, and the peak position X_Max$X_{\mathit{Max}}$ is linked to the particle charge density according to σ∼D₀X_Max$\sigma \sim D_0{X}_{\mathit{Max}}$ where D₀$D_0$ is the particle diameter. The PACTS is successfully applied to organic latex, aluminum and silicon oxide particles of positive or negative charge using poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). The protocol is also optimized with respect to important parameters such as pH and concentration, and to the polyelectrolyte molecular weight. The advantages of the PACTS technique are that it requires minute amounts of sample and that it is suitable to a broad variety of charged nano-objects.