title: Discovery of the surface polarity gradient on iridescent Morpho butterfly scales reveals a mechanism of their selective vapor response.
abstract: For almost a century, the iridescence of tropical Morpho butterfly scales has been known to originate from 3D vertical ridge structures of stacked periodic layers of cuticle separated by air gaps. Here we describe a biological pattern of surface functionality that we have found in these photonic structures. This pattern is a gradient of surface polarity of the ridge structures that runs from their polar tops to their less-polar bottoms. This finding shows a biological pattern design that could stimulate numerous technological applications ranging from photonic security tags to self-cleaning surfaces, gas separators, protective clothing, sensors, and many others. As an important first step, this biomaterial property and our knowledge of its basis has allowed us to unveil a general mechanism of selective vapor response observed in the photonic Morpho nanostructures. This mechanism of selective vapor response brings a multivariable perspective for sensing, where selectivity is achieved within a single chemically graded nanostructured sensing unit, rather than from an array of separate sensors.
authors.affiliation: General Electric Global Research Center, Niskayuna, NY 12309.
authors.forename: Radislav A
authors.initials: RA
authors.lastname: Potyrailo
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Starkey
authors.forename: Peter
authors.initials: P
authors.lastname: Vukusic
authors.forename: Helen
authors.initials: H
authors.lastname: Ghiradella
authors.forename: Milana
authors.initials: M
authors.lastname: Vasudev
authors.forename: Timothy
authors.initials: T
authors.lastname: Bunning
authors.forename: Rajesh R
authors.initials: RR
authors.lastname: Naik
authors.forename: Zhexiong
authors.initials: Z
authors.lastname: Tang
authors.forename: Michael
authors.initials: M
authors.lastname: Larsen
authors.forename: Tao
authors.initials: T
authors.lastname: Deng
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhong
authors.forename: Manuel
authors.initials: M
authors.lastname: Palacios
authors.forename: James C
authors.initials: JC
authors.lastname: Grande
authors.forename: Gilad
authors.initials: G
authors.lastname: Zorn
authors.forename: Gregory
authors.initials: G
authors.lastname: Goddard
authors.forename: Sergey
authors.initials: S
authors.lastname: Zalubovsky
mesh_terms: D000825:Animal Structures / Q000033:anatomy & histology* / Q000187:drug effects; D000818:Animals; D002080:Butterflies / Q000033:anatomy & histology* / Q000187:drug effects; D003198:Computer Simulation; D055620:Optical Phenomena; D010100:Oxygen / Q000494:pharmacology; D010858:Pigmentation / Q000187:drug effects; D015203:Reproducibility of Results; D013499:Surface Properties; D014835:Volatilization / Q000187:drug effects
chemical_list: D010100:Oxygen
keywords: image analysis; multivariable sensing; spectral analysis; surface characterization; transmission electron microscopy
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