Nanostructured Silver Arrays for SERS Fabricated within Block copolymer Nanotemplates
| Autor: | Szu-yu Shih, 施思羽 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 Tailor-made templates through self-assembly of block copolymers are capable of fabricating technologically nanostructured substrates. In this thesis, a sample but robust method is demonstrated to fabricate arrays of silver nanostructures with morphological diversity and a tunable adjacent gap for large area surface-enhanced Raman spectroscopy (SERS) substrates. First, nanostructured silver arrays of adjustable particulate size and inter-particle distance were fabricated by block copolymer templates for SERS substrates. The templates were formed by polystyrene-block-poly(2-vinylpyridine), P(S-b-2VP), micelles. The silver arrays with various surface coverage were prepared by spin-coating from o-xylene solution of varied polymer concentration (0.3 and 0.8 wt%). Photochemical reduction was applied to reduce silver ions after the P(S-b-2VP) micellar films were immersed in ethanol containing AgNO3. The interplay between the reduction of Ag+ and the removal of the P(S-b-2VP) template during UV-exposure for various time intervals affect the growth and spatial order of Ag nanoparticles, which in turn influences their SERS properties. Moreover, polystyrene-block-poly(4-vinylpyridine) was used to produce spherical micellar templates and cylindrical micellar templates through solvent annealing. Nanoporous and nanogrooves templates were made when spherical micellar templates and cylindrical micellar templates were immersed in ethanol. Spherical micelles, cylindrical micelles, nanoporous, and nanogrooves were utilized to fabricate silver arrays. Petal-like cluster, fingerprint clusters, network clusters and reverse fingerprint clusters were produced by reducing silver salts in BCP templates. Through long time of Ar plasma treatment, petal-like clusters and fingerprint clusters could maintain the order of spherical micellar templates and cylindrical micellar templates. Furthermore, reverse fingerprint clusters with R6G adsorption had the strongest SERS enhancement through Ar plasma treatment for 300 sec. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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