title: Novel controllable auxetic effect of linearly elongated supported polyelectrolyte multilayers with amorphous structure.
abstract: Polyelectrolyte multilayers (PEMs) deposited on flexible supports are promising candidates for many applications ranging from controlled wettability over stimuli responsive nanovalves to lithography free surface structuring. Since many potential applications involve elongation of these films, we investigated the effect of elongation on the PEM thickness and density with ellipsometry. To our surprise PEM films with known amorphous internal structure show auxetic behavior that depends on the PEM preparation condition. The measured refractive index was compared with simulated values using the Garnet equation to evaluate if the incorporation of water or air causes the observed phenomena.
authors.affiliation: Key Laboratory of Microsystems and Microstructures Manufacturing, Ministry of Education, Micro/Nano Technology Research Centre, Harbin Institute of Technology, Yikuang Street 2, Harbin 150080, China. johannes.frueh@hit.edu.cn
authors.forename: Johannes
authors.initials: J
authors.lastname: Frueh
authors.forename: Gerald
authors.initials: G
authors.lastname: Reiter
authors.forename: Helmuth
authors.initials: H
authors.lastname: Möhwald
authors.forename: Qiang
authors.initials: Q
authors.lastname: He
authors.forename: Rumen
authors.initials: R
authors.lastname: Krastev
mesh_terms: D002712:Chlorides / Q000737:chemistry; D004573:Electrolytes / Q000737:chemistry*; D008958:Models, Molecular; D011094:Polyethyleneimine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D012031:Refractometry; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D002712:Chlorides; D004573:Electrolytes; D011108:Polymers; D011137:Polystyrenes; D014867:Water; C003321:polystyrene sulfonic acid; D011094:Polyethyleneimine