Replication of polypyrrole with photonic structures from butterfly wings as biosensor

Abstract

Polypyrrole (PPy) with photonic crystal structures were synthesized from Morpho butterfly wings using a two-step templating process. In the first step photonic crystal SiO2 butterfly wings were synthesized from Morpho butterfly wings and in the second step the SiO2 butterfly wings were used as templates for the replication of PPy butterfly wings using an in situ polymerization method. The SiO2 templates were then removed from the PPy butterfly wings using a HF solution. The hierarchical structures down to the nanometer level, especially the photonic crystal structures, were retained in the final PPy replicas, as evidenced directly by field-emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM). The optical properties of the resultant PPy replicas were investigated using reflectance spectroscopy and the PPy replicas exhibit brilliant color due to Bragg diffraction through its ordered periodic structures. The preliminary biosensing application was investigated and it was found that the PPy replicas showed a much higher biological activity compared with PPy powders through their response to dopamine (DA), probably due to the hierarchical structures as well as controlled porosity inherited from Morpho butterfly wings. It is expected that our strategy will open up new avenues for the synthesis of functional polymers with photonic crystal structures, which may form applications as biosensors. Abstract: Photonic crystal polypyrrole (PPy) butterfly wings were synthesized from Morpho butterfly wings by using a two-step templating process. In the first step photonic crystal SiO 2 butterfly wings were synthesized from Morpho butterfly wings and in the second step the obtained SiO 2 replicas were used as templates for the duplication of PPy butterfly wings by using an in situ polymerization method. The SiO 2 templates were then removed from the PPy butterfly wings using a HF solution. The precise structures of the replicas were characterized by using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM). Molecular structure and the composition of the PPy replicas were further characterized by Fourier infrared spectroscopy (FT-IR) and energy-dispersive X-ray spectroscopy (EDS), respectively. It was confirmed that the photonic crystal PPy replicas were made of pure PPy. The optical properties of 2 the resultant PPy replicas were investigated by using reflectance spectroscopy and the PPy replicas exhibit brilliant color due to Bragg diffraction through its ordered periodic structures. The primary response of the replicas to dopamine (DA) as a biosensor was investigated and it was found that the PPy replicas showed a much higher biological activity compared with PPy powders, probably due to the hierarchical structures as well as controlled porosity inherited from Morpho butterfly wings. It is expected that our strategy will open up new avenues for the synthesis of functional polymers with photonic crystal structures, which can form the basis of p...

Titanium Dioxide Photonic Crystals with Enhanced Photocatalytic Activity: Matching Photonic Band Gaps of TiO2 to the Absorption Peaks of Dyes

“…Photonic crystals (PCs) have recently been studied extensively because of their photonic band gaps and the unique ways of controlling the propagation of light. , In addition, photonic crystals also possess unique structural properties and interesting optical properties, such as large surface area, multiple scattering, and slow photon (SP) effect, which has been widely used in the field of reflective polarizers, sensors, − solar cells, − and photocatalysis . For photonic crystals photocatalyst, one of the most intriguing properties for periodic photonic structures is the high surface/volume fractions and interconnected pores, which facilitates mass transport and light harvesting. , Cai et al prepared the TiO 2 inverse opals, which showed the enhanced activity in benzoic acid photodegradation as a results of the increased path length of light within the catalysts and the large specific surface areas .…”

Morpho peleides butterfly wing imprints as structural colour stamp

“…The second step was unique, compared to previous studies [24,52,61], and was intended to conduct a direct, fast, simple, and suitable negative imprint of the upper-wing surface of a Morpho peleides containing the veins of the wing piece, the upper laminae of the numerous cover scales, and the transition spaces between. The mounted specimen was treated with Pioloform powder (Polyvinyl Butyral, Plano GmbH, Germany) dissolved in chloroform (Sigma-Aldrich, St. Louis, USA).…”

“…For industrial use low-tech/high-yield solutions are of interest since they lower costs and simplify production. However, currently only soft lithography methods applied in combination with electroforming or further methods offer possibilities for industrial use [10,20,21,41,42,47,52,[56][57][58]. There has been extensive research on the use of the soft lithography method as a mass stamping tool [8, 9, 22-24, 28, 40, 41, 47, 60].…”

Fabrication of the replica templated from butterfly wing scales with complex light trapping structures

“…The photonic structures of the colorful butterfly wing scales have been fabricated using soft lithography technique [31], low-temperature atomic layer deposition [32,33], colloidal self-assembly, sputtering and atomic layer deposition, even combining all these layer deposition techniques together [34]. Not only sorts of surface processing technology but also a variety of materials were employed to fabricate replicas of the multi-layered scales on the surface of butterfly wing, such as polyelectrolyte multilayer films [35], carbon nanotube [36], polypyrrole [37], oxidizing material include SiO 2 [38], Bi 2 WO 6 [39], Fe 3 O 4 [40], SnO 2 [41] and so on. In addition, some works were also focused on metallic replicas [42,43] and polymer replicas [44,45].…”