(54e) Preparation of Novel Composite Materials Via CO-Coagulation of Nanoparticles

Authors: 
Rima, S., University of Fribourg
Lattuada, M., University of Fribourg

Since the term ‘nanocomposites’ has been proposed for the first time by Theng in 1970, the science dealing with these materials has arisen at the border of different areas of knowledge.

Numerous procedures for the preparation of nanocomposite materials have been investigated in order to generate materials with controlled features, which is still one of the great challenges in nanotechnology.
The purpose of this work is to use the extended and large knowledge of self-assembly behavior of spherical nanoparticles in aqueous solutions and its dependence on interparticle interactions for the preparation of various polymeric nanoparticles and the investigation of their self-assembly, to generate hybrid nanostructured composites.
The nanocomposites are prepared by blending together two colloidal suspensions made of charged particles. The first one is a suspension of hard silica nanoparticles (20 nm diameter) at different concentrations, while the second one consists of soft poly(butyl acrylate/methyl methacrylate) copolymer particles (80 nm diameter). The advantage of working in aqueous suspensions is that interparticles interactions of charged nanoparticles can be controlled. In order to investigate the specific role of such interactions on the final structure and mechanical properties of the materials, the nanocomposites have been synthetized following three different assembly strategies. The first one consists of simply mixing of stable particle suspensions with same surface charge. In the second case, instead, the filler particles were subject to aggregation and gelation while the matrix particles remained in stable suspension. The last case is that of hetero-aggregation of silica and rubber particles suspensions bearing opposite surface charges.
The solvent (i.e., water) was removed from all samples, which have been annealed, giving rise to nanostructured polymeric composites. All samples structure and mechanical properties have been characterized using different techniques (SAXS, AFM, SEM, tensile tests).