title: Helical Microfilaments with Alternating Imprinted Intrinsic Curvatures.
abstract: There has been an intense research for developing techniques that can produce filaments with helical shapes, given the widespread of potential applications. In this work, how helices with different curvatures can be precisely imprinted in microfilaments is shown. It is also shown that using this technique, it is possible to produce, in a single fiber, helices with different curvatures. This striking and innovative behavior is observed when one side of the stretched filaments is irradiated with UV light, modifying the mechanical properties at surface. Upon release, the regions with higher curvature start to curl first, while regions with lower intrinsic curvature remain stretched until start to curl later. The results presented here can be important to understand why structures adopt a helical shape in general, which can be of interest in nanotechnology, biomolecular science, or even to understand why plant filaments curl.
authors.affiliation: Departmento de Física/I3N - Universidade de Aveiro, Campus Universitario de Santiago, 3810-193, Aveiro, Portugal.|Departamento de Ciência dos Materiais and CENIMAT/I3N Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
authors.forename: Pedro Emanuel Santos
authors.initials: PE
authors.lastname: Silva
authors.affiliation: Departamento de Ciência dos Materiais and CENIMAT/I3N Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
authors.forename: Maria Helena
authors.initials: MH
authors.lastname: Godinho
mesh_terms: D004548:Elasticity; D008832:Microchemistry / Q000379:methods*; D054802:Molecular Imprinting; D036103:Nanotechnology
keywords: electrospinning; helices; intrinsic curvature; urethane/urea elastic microfilaments