Hydrophobicity-induced drying transition in alkanethiol self-assembled mono-layer water interface

Lakshminarayanan, V.; Sur, Ujjal Kumar

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/873

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DC Field	Value	Language
dc.contributor.author	Lakshminarayanan, V.	-
dc.contributor.author	Sur, Ujjal Kumar	-
dc.date.accessioned	2005-12-26T09:01:55Z	-
dc.date.available	2005-12-26T09:01:55Z	-
dc.date.issued	2003-08	-
dc.identifier.citation	Pramana, 2003, Vol. 61, p361-371.	en
dc.identifier.issn	0304-4289	-
dc.identifier.uri	http://hdl.handle.net/2289/873	-
dc.description	Proceedings of the international conference on liquid crystals and other soft materials held in 2002 at the Raman Research Institute, 2003.	en
dc.description.abstract	During the course of our investigation of the electron transfer properties of some redox species through highly hydrophobic long chain alkanethiol molecules on gold in aqueous and nonaqueous solvents, we obtained some intriguing results such as unusually low interfacial capacitance, very high values of impedance and film resistance, all of which pointed to the possible existence of a nanometer size interfacial gap between the hydrophobic monolayer and aqueous electrolyte. We explain this phenomenon by a model for the alkanethiol monolayer–aqueous electrolyte interface, in which the extremely hydrophobic alkanethiol film repels water molecules adjacent to it and in the process creates a shield between the monolayer film and water. This effectively increases the overall thickness of the dielectric layer that is manifested as an abnormally low value of interfacial capacitance. This behaviour is very much akin to the ‘drying transition’ proposed by Lum, Chandler and Weeks in their theory of length scale dependent hydrophobicity. For small hydrophobic units consisting of apolar solutes, the water molecules can reorganize around them without sacrificing their hydrogen bonds. Since for an extended hydrophobic unit, the existence of hydrogen bonded water structure close to it is geometrically unfavourable, there is a net depletion of water molecules in the vicinity leading to the possible creation of a hydrophobic interfacial gap.	en
dc.format.extent	125880 bytes	-
dc.format.mimetype	application/pdf	-
dc.language.iso	en	en
dc.publisher	Indian Academy of Sciences, Bangalore, India.	en
dc.rights	Indian Academy of Sciences, Bangalore, India.	en
dc.subject	Hydrophobicity	en
dc.subject	Hydrophobic gap	en
dc.subject	Self-assembled monolayer	en
dc.subject	Length scale dependent hydrophobicity	en
dc.subject	Interfacial capacitance	en
dc.subject	Uncompensated solution resistance	en
dc.title	Hydrophobicity-induced drying transition in alkanethiol self-assembled mono-layer water interface	en
dc.type	Article	en
Appears in Collections:	Research Papers (SCM)

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