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Titolo:
MOLECULAR GRADIENTS OF OMEGA-SUBSTITUTED ALKANETHIOLS ON GOLD - PREPARATION AND CHARACTERIZATION
Autore:
LIEDBERG B; TENGVALL P;
Indirizzi:
LINKOPING UNIV,APPL PHYS LAB S-58183 LINKOPING SWEDEN
Titolo Testata:
Langmuir
fascicolo: 10, volume: 11, anno: 1995,
pagine: 3821 - 3827
SICI:
0743-7463(1995)11:10<3821:MGOOAO>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
SELF-ASSEMBLED MONOLAYERS; NORMAL-ALKYL CHAINS; H STRETCHING MODES; WETTABILITY GRADIENT; ORGANIC MONOLAYERS; SOLID-SURFACES; STRUCTURAL CHARACTERIZATION; PROTEIN ADSORPTION; ELECTRON-TRANSFER; THIOL MONOLAYERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
49
Recensione:
Indirizzi per estratti:
Citazione:
B. Liedberg e P. Tengvall, "MOLECULAR GRADIENTS OF OMEGA-SUBSTITUTED ALKANETHIOLS ON GOLD - PREPARATION AND CHARACTERIZATION", Langmuir, 11(10), 1995, pp. 3821-3827

Abstract

A general methodology capable of generating a molecular, chemical concentration gradient on a solid substrate in one surface dimension is presented. Although the method can be extended to more than one surfacedimension, and to a variety of molecule/substrate systems, we have chosen to demonstrate it by utilizing thiols on gold as the model system. The gradients are prepared by cross-diffusing omega-substituted alkanethiols, HS(CH2)(n)X (X = OH, CO2CH3, COOH, and CD3, n = 10-19), withor without fully deuterated chains, and simple n-alkanethiols, HS(CH2)(m)Y (Y = CH3, m = 9-17), toward each other from opposite ends of a polysaccharide matrix deposited on top of a gold substrate. The so-prepared gradients are characterized by a number of techniques, including ellipsometry, contact angle measurements, and infrared reflection absorption spectroscopy (IRAS). The observed ellipsometric thicknesses andthe limiting contact angles of the gradient assemblies agree very well with the values obtained from the corresponding single component andmixed self-assembled monolayers. The infrared data furthermore suggest that the entire gradient is composed of well-organized and densely packed all-trans hydrocarbon chains for thiols with chain length >10. The lateral dimensions of the gradient regions vary between 4 and 8 mm for the combination diffusion pairs employed in this study. The upper and lower values account for diffusion pairs with long and short hydrocarbon chains, respectively. It must be stressed, however, that the infrared and ellipsometric techniques only can provide information aboutthe molecular organization on the macroscopic scale because of the relatively large spot size (approximate to 1 mm) used in the experiments. Scanning probe microscopy must be employed to further investigate the mechanism of gradient formation, the molecular concentration profile, and mixing behavior on the microscopic (molecular) scale. We believe, however, that the large number of chemical and structural combinations attainable with the present approach can be used to address a broadrange of surface physics/chemistry problems in material science and generate novel and unique model organic architectures. We discuss briefly the potential applications of these novel gradients in areas of relevance to molecular recognition and biosensing.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 07:06:48