Permeability profile of water-filled PACA nanocapsules

Christian Erdmann, Universität Duisburg-Essen, Essen, Deutschland
Christian Mayer, Universität Duisburg-Essen, Essen, Deutschland

The permeability of polymer walls of poly(alkyl cyanoacrylate) (PACA) nanocapsules is studied using a variety of tracer molecules of different size and polarity. In addition, the influence of the organic tracer molecules on the permeability for water is shown.

As expected, the results clearly show that the capsule membrane permeability depends on the size of the tracer molecule: the exchange rate of polyethylene glycols continuously decreases with increasing chain length. In addition, the permeation rate varies with the polarity of the tracer molecule: molecules of lower polarity exchange faster than more polar ones. The dependence between permeability and polarity is underlined using the concept of Hansen solubility parameters.

The nanocapsules are prepared via the Ouzo effect and interfacial polymerization. Afterwards the permeability is studied via pulsed field-gradient nuclear magnetic resonance. Particle tracking is used to optimize the obtained fit curves in relation to the experimental data.

In a next step, the PACA nanocapsules can be modified using click chemistry to bind an initiator at the capsule surface which offers the opportunity to modify the nanocapsules via atom radical transfer polymerization. The final aim is to achieve a change in the permeation rate for different tracer molecules through the capsule membranes.

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