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1611429 
Journal Article 
Characterization of Nanoporous Polystyrene Thin Films by Environmental Ellipsometric Porosimetry 
Vayer, M; Thi Hoa Nguyen; Grosso, D; Boissiere, C; Hillmyer, MA; Sinturel, C 
2011 
1 
Macromolecules
ISSN: 0024-9297
EISSN: 1520-5835 
44 
22 
8892-8897 
WOS:000296893400023 
Environmental ellipsometric porosimetry (EEP) was used to
characterize nanoporous polystyrene thin films containing cylindrical channels oriented
perpendicularly to the surface of the film. These samples were prepared from the selective
etching of polylactide from a se:If-assembled polystyrene-polylactide block copolymer.
Isopropanol adsorption-desorption isotherms were obtained from the refractive index variations
induced by the adsorption and condensation in the pores. Mean pore size and pore-size
distributions were consistent with the values obtained by AFM, SEM, and GI-SAXS. More detailed
analysis of the EEP data revealed that the topology of the porous structure was more tortuous
than the simple picture of vertically oriented nanochannels might suggest. This was confirmed by
preparing inorganic replicas that provided a hard negative copy of the porous network of the
film. Microscopy on these replicas confirmed that a fraction of the channels exhibited a U-shape
and thus were not perfectly perpendicular to the film surface.