Water adsorption on etched hydrophobic surfaces of L-, D- and DL-valine crystals

Juan José Segura Sugranes
Elsevier, 2014
Journal paper

Abstract

The adsorption of water on etched (001) surfaces of L-, D- and DL-valine crystals has been characterized by atomic force microscopy (AFM) using different operational modes (contact, non-contact and electrostatic) above and below the dew point, the temperature at which water vapor from humid air condenses into liquid water at constant atmospheric pressure. The analysis of the images suggests the formation of aggregates of solvated valine molecules that easily diffuse on the hydrophobic terraces only constrained by step barriers of the well-defined chiral parallelepipedic patterns induced by the etching process. (C) 2013 Elsevier B.V. All rights reserved.

Official source

https://infoscience.epfl.ch/record/198014?ln=en

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related concepts

Related publications

, ,

A micro pump was integrated into a scanning force microscope probe for circulating liquid through its hollow cantilever and tip. The interior cross section of the cantilever was 2.25 mu m x 3.75 mu m. All fluidic parts were made of SiO2, while the tip apex was made of Si3N4. The key fabrication techniques were silicon wafer bonding and wet-oxidation. The pumping mechanism was relying on the enhanced evaporation at an enlarged water/air interface at the exit of the microchannel. Capillary forces continuously wetted this interfacial area, thus drawing the liquid through the system. At room temperature, a pump rate of 11 pl s(-1) was experimentally evaluated. The observed temperature dependence of the pump rate could be qualitatively understood by a plain model calculation. (C) 2007 Elsevier B.V. All rights reserved.

Elsevier2008

Atomic force microscopy study of the adsorption and electrostatic self-organization of poly(amidoamine) dendrimers on mica

Michal Borkovec, Ramon Pericet Camara

The adsorption behavior of poly(amidoamine) dendrimers to mica surfaces was investigated as a function of ionic strength and pH. The conformation and lateral distribution of the adsorbed dendrimers of generations G8 and G10 were obtained ex situ by tapping mode atomic force microscopy (AFM). The deposition kinetics of the dendrimers was found to follow a diffusion-limited process. Fractional surface coverage and pair correlation functions of the adsorbed dendrimers were obtained from the AFM images. The data are interpreted in terms of the random sequential adsorption (RSA) model, where electrostatic repulsion due to overlapping double layers is considered. Although the general trends typical for an RSA-determined process are well-reproduced, quantitative agreement is lacking at low ionic strengths.

American Chemical Society2004

Micropatterning of gold substrates based on poly(propylene sulfide-bl-ethylene glycol), (PPS-PEG) background passivation and the molecular-assembly patterning by lift-off (MAPL) technique

Jeffrey Alan Hubbell

Poly(propylene sulfide-bl-ethylene glycol) (PPS-PEG) is an amphiphilic block copolymer that spontaneously adsorbs onto gold from solution. This results in the formation of a stable polymeric layer that renders the surface protein-resistant when an appropriate architecture is chosen. The established molecular-assembly patterning by lift-off (MAPL) technique can convert a prestructured resist film into a pattern of biointeractive chemistry and a non-interactive background. Employing the MAPL technique, we produced a micron-scale PPS-PEG pattern on a gold substrate, and then characterized the patterned structure with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM). Subsequent exposure of the PPS-PEG/gold pattern to protein adsorption (full human serum) was monitored in situ; SPR-imaging (i-SPR) shows a selective adsorption of proteins on gold, but not on PPS-PEG areas. Analysis shows a reduction of serum adsorption up to 93% on the PPS-PEG areas as compared to gold, in good agreement with previous analysis of homogenously adsorbed PPS-PEG on gold. MAPL patterning of PPS-PEG block copolymers is straightforward, versatile and reproducible, and may be incorporated into biosensor-based surface analysis methods. (C) 2008 Elsevier B.V. All rights reserved.

2008