Composites of Polypyrrole with Micelles Nanospheres

Alternating polymers were used to obtain self assembling micelles – nanospheres. In the polymer structure every second unit is maleic anhydride (poly(maleic anhydride alt-1-octadecene)), as upon spontaneous hydrolysis anhydride groups are transformed into carboxyl groups resulting in stability of thus obtained particles (micelles) in aqueous environment [1]. Crosslinking can be achieved in course of reaction with bis(hexamethylene)triamine.

Thus obtained nanospheres have size close to ~150 nm and negative surface charge, due to the presence of carboxyl groups on the surface. The above mentioned structures were incorporated into polypyrrole films, obtained electrochemically, where micelles with ionized carboxyl groups served as negative counter ions. The polymer was characterized by stable voltammetric responses and  very well separated potential ranges corresponding to anion– and cation–exchanging properties (in contrast to classical polypyrrole / polystyrenesulfonate films, where overlapping of these ranges was observed). Potentiometric sensitivity of these films can be switched between anionic and cationic characteristics by appropriate conditioning / polarization. Polypyrrole / nanospheres composites exhibit also significant pH sensitivity both in voltammetric and potentiometric mode, resulting from the presence of carboxyl groups.

Controllable sensitivity to various groups of ions and possibility of ions accumulation is promising for analytical applications of these composites, because of the fact that nanospheres can be loaded with compounds of choice, e.g. ionophores or catalytic centers [2].

 

1. T. Pellegrino, L. Manna, S. Kudera, T. Liedl, D. Koktysh, A. L. Rogach,  S. Keller, J. Rädler,
   G. Natile, W. J. Parak, Hydrophobic nanocrystals coated with an amphiphilic polymer shell: a general route to water soluble nanocrystals. Nano Lett. 2004, 4. 703-707.
2. A. Kisiel, K. Kłucińska, Z. Głębicka, M. Gniadek, K. Maksymiuk, A. Michalska, Alternating polymer micelle nanospheres for optical sensing. Analyst, 2014, 139. 2515-2524.