Environment-controlled tethering by aggregation and growth of phosphonic acid monolayers on silicon oxide
Phosphonic acid monolayers are being considered as versatile surface modification agents due to their unique ability to attach to surfaces in different configurations, including mono-, bi-, or even tridentate arrangements. Tethering by aggregation and growth (T-BAG) of octadecylphosphonic acid (ODPA...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 28(2012), 21 vom: 29. Mai, Seite 8046-51 |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2012
|
| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Membranes, Artificial Organophosphonates Phosphorous Acids phosphonic acid 13598-36-2 Silicon Dioxide 7631-86-9 |
| Zusammenfassung: | Phosphonic acid monolayers are being considered as versatile surface modification agents due to their unique ability to attach to surfaces in different configurations, including mono-, bi-, or even tridentate arrangements. Tethering by aggregation and growth (T-BAG) of octadecylphosphonic acid (ODPA) on silicon oxide surfaces has proven to be a robust method to establish a strong chemical bond. However, it requires a long processing time (> 48 h) that is a substantial drawback for industrial applications. We demonstrate here that the humidity level during processing is the most important parameter controlling the reaction. Using in situ Fourier Transform Infrared Spectroscopy (FTIR), we first show that the initially physisorbed layer obtained upon immersion in ODPA is composed of well-ordered bilayers and only reacts with the SiO(2) surface at 140 °C. Importantly, we show that the presence of water at the interface (determined by the humidity level) greatly influences the reaction time and completion. In humid environments (relative humidity, RH > 40%), there is no reaction, while in dry environments (RH < 16%), the reaction is essentially instantaneous at 140 °C. Ab initio calculations and modeling confirm that the degree of chemical reaction with the surface OH groups depends on the chemical potential (i.e., concentration) of interfacial water molecules. These findings provide a workable modification of the traditional T-BAG method consistent with many industrial applications |
|---|---|
| Beschreibung: | Date Completed 21.09.2012 Date Revised 15.11.2012 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/la300709n |