This paper describes recent results concerning multimodal fluoropolymer dispersions having excellent film forming behaviour and particle packing properties. These high-performance fluoropolymer dispersions have been developed thanks to Solvay Solexis proprietary technology of microemulsion polymerisation which permits to obtain bimodal particle size distributions, not only by blending standard fluoropolymer dispersions (particle size about 250 nm) with nano-latexes ranging from 10 to 60 nm, but also directly from polymerisation, by using specific fluorosurfactant system in the nucleation stage, when competitive homogeneous-coagulative and droplet nucleation mechanisms take place. It has been found that PTFE bimodal dispersions have optimal film forming and particle packing behaviour at a size ratio of about 0,15, corresponding to the best fit of the random close packing model, while no significant improvements are observed when the aforesaid size ratio is 0,3.
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