Modification of Conducting Polymer Thin Film Interfaces Using Self-Assembled Monolayers Containing Transition Metal Complexes

2002 ◽  
Vol 734 ◽  
Author(s):  
David M. Sarno ◽  
Sudhindra Prasad ◽  
Wayne E. Jones ◽  
Luis J. Matienzo
Keyword(s):  
Conjugated Polymer ◽  
Fused Silica ◽  
Self Assembled Monolayers ◽  
Salt Form ◽  
Secondary Nucleation ◽  
Polymer Thin Film ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Ruthenium Porphyrin

ABSTRACTThin films of polyaniline (PANi) have been in-situ deposited onto fused silica plates modified with ruthenium porphyrin and polypyridyl complexes coordinated to self-assembled monolayers of pyridyl-terminated alkylsilanes. Based on UV-vis and AFM studies, PANi exhibits a slower deposition rate and an earlier onset of secondary nucleation on the metal complex-modified interfaces. Electrical conductivity of the HCl-doped emeraldine salt form of PANi is increased to as high as 40 S/cm, relative to <1 S/cm on bare silica, measured under the same conditions and in the absence of any external modification to the polymer films. These changes are attributed to favorable π interactions between the aromatic surface species and the conjugated polymer that lead to a more expanded coil conformation for PANi.

Spectral and cyclic voltammetric characterization of self-assembled monolayers on gold of pyrene end-labeled oligonucleotide duplexes

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1077-1084 ◽  
Author(s):  
R Scott Reese ◽  
Marye Anne Fox
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Surface Emission ◽  
Assembled Monolayers ◽  
Oligonucleotide Duplex ◽  
Self Assembled ◽  
Duplex Formation

Self-assembled monolayers of sulfur-terminated oligonucleotide duplexes were formed on flat gold surfaces, either by exposure of a self-assembled monolayer bearing one oligonucleotide strand to the complementary strand or by preformation of a oligonucleotide duplex that was then deposited on a fresh gold surface. Virtually identical spectral behavior was observed whether the duplex was produced before deposition or by in situ complementary association. With a duplex bearing an appropriate pyrene end-label, the resulting thin film was photoresponsive. Surface emission measurements show no evidence for pyrene aggregation on the modified surfaces. The polarity of the photocurrent, reflecting photoinduced electron transfer initiated by photoexcitation of pyrene, is opposite that expected from the oligonucleotide-mediated reduction of the appended pyrene excited state.Key words: oligonucleotide, self-assembled monolayer, duplex formation, photoelectrochemistry, surface emission.

scholarly journals Adsorption and desorption of self-assembled L-cysteine monolayers on nanoporous gold monitored by in situ resistometry

2019 ◽  
Vol 10 ◽  
pp. 2275-2279
Author(s):  
Elisabeth Hengge ◽  
Eva-Maria Steyskal ◽  
Rupert Bachler ◽  
Alexander Dennig ◽  
Bernd Nidetzky ◽  
...  
Keyword(s):  
Gold Surface ◽  
Research Field ◽  
Nanoporous Gold ◽  
Self Assembled Monolayers ◽  
Initial Surface ◽  
Resistance Change ◽  
Adsorption And Desorption ◽  
Assembled Monolayers ◽  
Self Assembled

Surface modifications of nanoporous metals have become a highly attractive research field as they exhibit great potential for various applications, especially in biotechnology. Using self-assembled monolayers is one of the most promising approaches to modify a gold surface. However, only few techniques are capable of characterizing the formation of these monolayers on porous substrates. Here, we present a method to in situ monitor the adsorption and desorption of self-assembled monolayers on nanoporous gold by resistometry, using cysteine as example. During the adsorption an overall relative change in resistance of 18% is detected, which occurs in three distinct stages. First, the cysteine molecules are adsorbed on the outer surface. In the second stage, they are adsorbed on the internal surfaces and in the last stage the reordering accompanied by additional adsorption takes place. The successful binding of cysteine on the Au surface was confirmed by cyclic voltammetry, which showed a significant decrease of the double-layer capacitance. Also, the electrochemically controlled desorption of cysteine was monitored by concomitant in situ resistometry. From the desorption peak related to the (111) surface of the structure, which is associated with a resistance change of 4.8%, an initial surface coverage of 0.48 monolayers of cysteine could be estimated.

Photochromic dithienylethenes characterized by in situ irradiation NMR-spectroscopy and electrochemically induced responsiveness on gold substrates

2019 ◽  
Vol 7 (45) ◽  
pp. 14088-14097
Author(s):  
Jonas von Irmer ◽  
Florian Frieß ◽  
Dominik Herold ◽  
Jonas Kind ◽  
Christina M. Thiele ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Self Assembled Monolayers ◽  
Gold Surfaces ◽  
Gold Substrates ◽  
Assembled Monolayers ◽  
Self Assembled

The photochromic and electrochemical switching capabilities of two dithienylethenes with different substitutions and their self-assembled monolayers on gold surfaces are characterized by in situ NMR-spectroscopy and cyclic voltammetry.

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