Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5369508 | Applied Surface Science | 2008 | 10 Pages |
Laser irradiation at 157Â nm of polymethylmethacrylate (PMMA) thin films induces major variations of polymer film thicknesses from sorption (absorption/desorption) of methanol and ethanol analytes in the gas phase as much as 400%, in comparison to the film thickness variation of the non-irradiated areas. The structural changes of irradiated areas involve scission of polymeric chains, cross-linking and formation of new bonds. In addition, 157Â nm induces surface and volume morphological changes in the nano/micro domain, with different shapes, depending on the irradiation conditions. The reversibility of the sorption processes suggests that the polymer swelling has its origin at the tendency of the system to increase its volume during sorption. The internal forces from sorption are higher than the weak dipole interactions between the polymer and the analytes and they are amplified following 157Â nm irradiation. A simple qualitative model explains adequately the experimental results. 157Â nm laser treatment forms the basis to engineer a novel class of polymer sensor arrays with enhanced detection efficiency of liquid/gas analytes.