Novel Modified Pyrrole Monomers, 2: Behaviour in Water Solutions

Abstract

Aggregate formation of modified pyrroles was investigated in water and water/ethanol mixtures by means of light scattering for novel reactive single-chain alkyl phosphonate containing pyrrole units. The influence of concentration, pH, temperature and organic solvents on the evolution of the vesicle size is discussed. Longchain alkyl phosphonates functionalized with pyrrole units form stable vesicles in water solutions. Lowering of the pH value results in a partial protonation of the phosphonate groups and in less electrostatic repulsion between the anionic groups, leading to larger vesicle diameters and higher tendency to aggregate. Addition of ethanol, as well as increase in temperature cause an increase in the aggregate size due to better solubility of alkyl phosphonates. The reactive vesicles are extremely interesting templates for oxidative polymerisation of pyrrole and they can provide the formation of novel particles based on conjugated polymers.  Koninklijke Brill NV, Leiden, 2008

Pyrrole-tailed imidazolium surface-active monomers: aggregation properties in aqueous solution and polymerization behavior

“…pC 20 values increased with the alkyl chain length, which confirmed a higher efficiency of surfactant activity upon increasing n. In our series, a slightly lower value of pC 20 The area occupied by a surfactant molecule at the air-water interface A min was calculated according to equation ( 3):…”

“…[18,19] The surfactant behavior of other pyrrole-based compounds including phosphonate-based ones, has also been studied. [20] Concomitantly, imidazolium and pyridinium-based surfactants bearing a terminal pyrrole group have been also used as structure-directing agent to elaborate ordered mesoporous silica structure. Pyrrole units were easily polymerized via chemical oxidation and, consequently, highly ordered hexagonal mesoporous silicas with aligned polypyrrole nanowires in channels were achieved.…”