Interfacial water and ice at organic and biological surfaces
a minimum sequence approach to investigate the possibilility of using the 37-mer, or smaller segments thereof, as building blocks for anti-freeze surfaces.
self-assembled monolayers of w-substituted alkanethiols bearing amide linked residues like -CH3 to mimic alanine and -CHCH3OH to mimic threonine will be assembled on gold substrates
During recent years, an increasing number of studies have
been dealing with the potential applications of self-assembled monolayers
(SAMs), in such diverse areas as molecular recognition, surface biology
and biochemistry, chemical force microscopy, metallization of organic materials,
corrosion protection, molecular crystal growth, alignment of liquid crystals,
pH-sensing devices, patterned surfaces on the µm scale, and lithographic
resists. In several of these areas, a fundamental understanding of the interaction
between SAMs and secondary adsorbates is crucial. For example, in biochemical
applications where water-organic interfaces are ubiquitous and in studies
of the molecular basis of wetting and of hydrogen bonding interactions,
the importance of water as the secondary adsorbate cannot be overestimated.
As a matter of further interest, the formation, ordering, and phase behavior
of interface-confined solid water films, i.e., ice, constitute a research
topic in its own right, with possible applications in astrophysical research,
biochemistry, and in the fundamental understanding of liquid water. For
these reasons, we are performing a series of model experiments to systematically
evaluate the interactions of water with a large set of SAMs of single and
mixed chemical functionalities.
The SAMs are mounted in a UHV system where they are cooled, dosed with water (D2O in most cases) and then examined with IRAS and TPD. Typically, water doses yielding a 1-10 Å overlayer (average thickness) are used. Some of the SAM functionalities that have been or currently are being investigated are:
mixtures of -CH3 and -OH
different kinds of gradient samples
Results of these investigations can be found in the following papers.
"Temperature-Programmed Desorption and Infrared
Studies of D2O Ice on Self-Assembled Alkanethiolate Monlayers: Influence of
Isak Engquist, Ingemar Lundström and Bo Liedberg
J. Phys. Chem. 99 (1995) p. 12257
"Hydrogen Bond Interaction between Self-Assembled
Monolayers and Adsorbed Water Molecules and Its Implications for Cluster Formation"
Isak Engquist, Magnus Lestelius and Bo Liedberg
J. Phys. Chem. 99 (1995) p. 14198
"Infrared Characterization of Amorphous
and Polycrystalline D2O Ice on Controlled Wettability Self-Assembled Alkanethiolate
Isak Engquist, Atul N. Parikh, David L. Allara, Ingemar Lundstršm and Bo Liedberg
J. Chem. Phys., accepted for publication
"D2O Ice on Controlled Wettability Self-Assembled
Alkanethiolate Monolayers: Cluster Formation and Substrate-Adsorbate Interaction"
Isak Engquist and Bo Liedberg
J. Phys. Chem. 100 (1996) p. 20089
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Last updated: 05/16/06