Nanosized hairy grains: A model system to understand the reinforcement

• Published in: Europhysics letters Vol. 36; no. 2; pp. 153 - 158
• Main Authors: Castaing, J.-C, Allain, C, Auroy, P, Auvray, L, Pouchelon, A
• Format: Journal Article
• Language: English
• Published: IOP Publishing 10.10.1996; EDP Sciences
• Subjects: 61.41.+e; 81.05.Qk; 82.70.Dd
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i1996-00202-4

We have prepared nanosized hairy grains by grafting long polydimethylsiloxane chains onto silica particles of radius $\approx15\rm\,nm$. The synthesis method allows the particles to keep in truly stable suspension at any stage of their preparation. In dilute suspension, these hairy grains behave as repulsive soft spheres. Above a certain concentration (of the order of $0.1\;{\rm g/cm}^3$), the polymer chains form bridges between the particles due to physical adsorption, which induces a gelation of the suspension. If the solvent is completely removed, a reinforced elastomer is formed. Its mechanical properties (which can be exceptionally good) are entirely determined by the design of the ultimate particles.