Response of polyelectrolyte layers to the SiO2 substrate charging as probed by XPS
Conger, C. P.
1757 - 1760
MetadataShow full item record
Please cite this item using this persistent URLhttp://hdl.handle.net/11693/22834
A single layer of the Cationic polyelectrolyte poly(allyamine) hydrochloride (PAH) deposited, using the layer-by-layer technique, on a silicon substrate containing 5 nm oxide layer is investigated by XPS while applying an external potential bias to the sample to control and manipulate the charge built-up on the oxide layer. Under application of a -10 V bias, the oxide layer is positively charged due to Photoemission process, evidenced by the measured Si2p binding energy of 104.4 eV. Application of a +10 V bias attracts the low energy neutralizing electrons, stemming from a hot filament, and leads to a negatively charged oxide layer, also evidenced by the measured Si2p binding energy of 102.9 eV. The single polyelectrolyte overlayer also responds to this polarity change of the oxide layer underneath by displaying a somewhat larger shifts both in the C1s and Nls peaks. In addition to the shifts in the positions, the N1s peaks undergo a significant intensity depletion, mostly on the positively charged -N+ component. We interpret this intensity depletion to be the result of reorientation of some of the dangling positively charged groups by moving toward the negatively charged oxide underlayer. To our knowledge this is the first time that a chemically specific response to an electrical stimuli is reported using XPS. A bilayer LbL film consisting of PAH and PSS, exhibits even a larger charging shift, but this time no intensity alteration is observed, most probably due to locking of the -N+ groups by the -SO3 + counterions of the second layer. © 2009 American Chemical Society.
Showing items related by title, author, creator and subject.
Nanoengineering Hybrid Supramolecular Multilayered Biomaterials Using Polysaccharides and Self-Assembling Peptide Amphiphiles Borges J.; Sousa M.P.; Cinar G.; Caridade S.G.; Guler M.O.; Mano J.F. (Wiley-VCH Verlag, 2017)Developing complex supramolecular biomaterials through highly dynamic and reversible noncovalent interactions has attracted great attention from the scientific community aiming key biomedical and biotechnological applications, ...
Orlov, A.; Ulianova, V.; Bogdan, O.; Pashkevich, G.; Biyikli, N.; Goldenberg, E.; Haider, A. (Institute of Electrical and Electronics Engineers Inc., 2015)The original results of two different types of ZnO nanostructures grown via hydrothermal synthesis on ZnO seed-layers coated by atomic layer deposition process on Si substrates were presented. Scanning electron microscopy ...
Yeşil, M.Ş.; Güdükbay, U. (2006)A framework for realistic rendering of a multi-layered human body model is proposed in this paper. The human model is composed of three layers: skeleton, muscle, and skin. The skeleton layer, represented by a set of joints ...