Polystyrene-block-polyisoprene nanofiber fractions.: 1.: Preparation and static light-scattering study

Block copolymer nanofibers may be viewed as the macroscopic counterparts of polymer chains or supra-polymer chains. Well-characterized nanofiber fractions with narrow length distributions are required to facilitate their study by techniques such as viscometry and dynamic light scattering. Polystyrene-block-polyisoprene (PS-h-PI) nanofibers were prepare in this shady by stirring S2Cl2-treated PS-b-PI films in THF to separate and disperse the cross-linked Pi cylindrical domains. Nanofiber fractions were obtained by combining centrifugation fractionation and ultrasonication. These fractions were characterized lay transmission electron microscopy to obtain their length distribution functions and static light scattering to yield the weight-average molar masses and z-average radii of gyration. A quantitative analysis of the radius of gyration values revealed that the PS-b-PI nanofibers had a persistence lend of similar to200 nm in THF.