SERS active systems of water-soluble polythiophene and plasmonic nanoparticles: preparation and optical properties

Abstract

SERS Active Systems with Water Soluble PolythiopheneAbstract. Aggregated systems of silver (Ag) and gold (Au) nanoparticles coated with cationic polythiophene were prepared, which showed optical properties typical for strongly coupled plasmonic excitations. The procedure allowed tune up the 3-dimensional arrangement of nanoparticles assembly for achieving strong SERS effects at the excitation wavelength depending on the polymer concentration. By combination with an anionic derivative of polythiophene thin multilayer films composed of alternating anionic and cationic polythiophene with mutually interacting plasmonic Au nanoparticles were successfully prepared using layer-by-layer deposition.

Alcohol-soluble bis(tpy)thiophenes: new building units for constitutional dynamic conjugated polyelectrolytes

“…Each shows a medium to low intensity band of coordinated tpy groups: (i) ring-stretching modes at 1610 to 1600 cm À1 , 1570 cm À1 and 1535 to 1548 cm À1 , (ii) in plane deformation mode at 1288 cm À1 , and (iii) asymmetric ring breathing mode at about 1025 cm À1 . 38,39 However, the strongest bands in these spectra are bands of thiophene-2,5-diyl units, 33,[40][41][42][43] which appeared at 1484, 1450 and 1405 cm À1 for P Zn M-type dynamers, and at 1484, 1457 and 1411 to 1417 cm À1 for P Zn B-type dynamers. Different end-capping of hexyl-groups has very little impact on the spectral pattern.…”

Polythiophene-based conjugated polyelectrolyte: Optical properties and association behavior in solution

“…Conformations and intermolecular interactions are fixed by strong electrostatic forces when transferred from solution to solid state. It can be even more pronounced, e.g., in the fabrication of layer-by-layer assemblies of the polyelectrolytes of the opposite charge [7], or in the composites with charged surfaces such as nanoparticles [8][9][10][11]. Ionic polythiophenes are a peculiar group among other CPEs because optical properties of polythiophenes are strongly influenced by two parameters.…”

Molecular Design, Synthetic Strategies, and Applications of Cationic Polythiophenes

“…Regioregular 199 was subsequently converted to poly­(3-[6-(1′-methylimidazolium-3-yl)­hexyl]-thiophene-2,5-diyl) bromide (P3HT-Im) 202 with 1-methylimidazole (Scheme ). Likewise, the group of Clément prepared poly­(3-[ n -(1′-methylimidazolium-3-yl)­alkyl]-thiophene-2,5-diyl) bromide with alkyl side chains R = butyl 198 , hexyl 199 , and octyl 200 in 2011. These polymer precursors 198 – 200 were synthesized using GRIM reaction (Scheme ), whereby the synthesis utilized a Williamson etherification of the dibromide ( x = 1, c = 4; x = 2, c = 6; x = 3, c = 8) to provide 215a – c .…”

“…Regioregular 199 was subsequently converted to poly(3-[6-(1′-methylimidazolium-3-yl)hexyl]-thiophene-2,5-diyl) bromide (P3HT-Im) 202 with 1-methylimidazole (Scheme 30). 157 Likewise, the group of 3). The precursor polymer 199 was obtained with M n of 5000 g mol −1 and a Đ of 1.39.…”

“…108 Herein, the plasmonic properties of the Ag-metal nanoparticles and the semiconductive properties of thiophene-based conjugated polymers were exploited. The resulting aggregated composite exhibited strong electromagnetic field enhancement that is polymer concentration dependent when observed using surface enhanced Raman scattering (SERS) 157 and mean interparticle distance capable of plasmonic effects. Furthermore, the aggregated assembly formed via electrostatic interaction between the monolayer of polymer 202 and the surface of the silver nanoparticle, balanced the charges between the two and gave a zeta potential of zero charge.…”