The use of particles with anisotropic shape is of significant interest since it allows fabrication of structures with special symmetries and degree of packing, as well as with anisotropic properties. Rod-like polymer particles could have interesting properties and could find many practical applications; however, few methods for the production of such particles are available. In this work we introduced and investigate a method for synthesis of a new class of polymeric nanorods and nanofibrils based on emulsion polymerization using wormlike polymerizable micelles as template. Wormlike micelles are elongated and semiflexible aggregates of surfactant molecules. The equilibrium and dynamics of the micellar structures, however, are determined by a delicate balance of intermolecular forces that can be easily disrupted. In the current study it has been observed that addition of oils or polymers typically reduces the average micelle length and results in a dramatic decrease of the solution viscosity on the microstructure and loss of the highly elongated and entangled micelles. During the polymerization process, the viscosity is reduced by several orders of magnitude to a water-like value, and no viscoelasticity can be observed either visually or rheometrically. These data suggest a transition from rodlike to spherical micellar aggregates. A polymerizable surfactant, cetyltrimethylammonium 4-vinylbenzoate (CTVB), containing a polymerizable counterion, has been prepared and investigated with the purpose of “locking in” the micellar structure over the oil polymerization so that the template is less sensitive to environmental changes. Elongated particles and long polymer fibrils have been formed depending on cross linker concentration used, partially preserving the structure of the parent micelle upon polymerization.
marco.lattuada@unifr.ch
