I have flat combination electrode and pH-meter. As I understood, electrode should be immersed into drop of water on analysing surface, but are the volume and contact surface important in this case? It's slightly difficult for me to extrapolate the knowledge about pH onto solid surfaces.
I would suggest to try using contact angle measurements:
http://gmwgroup.harvard.edu/pubs/pdf/301.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a158596.pdf
http://www.ecf.utoronto.ca/~molly/publications/control%20of%20wettability...surface%20chemistry.pdf
http://gmwgroup.harvard.edu/pubs/pdf/260.pdf
http://144.206.159.178/ft/2957/77554/1310941.pdf
I believe that these and related publications should be reproduced in your system. I thin that a kind of "surface titaration" based on caontact angle measurements would be highyl relevant to your potential applications.
What is the form of the material you wish to characterize? In the case of powders (e.g. fillers) the acidity/basicity of the surface is frequently characterized by adhesion measurements using acidic and alkaline adherents (e.g. gases in inverse chromatography, or liquids together with the measurement of adhesion heat). Maybe you are interested in surface charge which is usually characteriezd by zeta potential measurement (plotted against th pH of the surrounding soution). Please specify your problem.
Thank you for reply. It's a plastic plate with a slightly acidic filler. I wouldn't like to make powder sample from it, but only thinking if it is possible to say something about acidity of its surface. I use flat-membrane combination electrode (this one: http://www.labsource.co.uk/shop/wtw-sentix%C3%82%C2%AE-sur-special-electrode-103-646-p-8030.html) which is suitable for paper, skin, films etc., but obtained values vary strongly and I'm not sure that this method is correct for my case. I think it's possible to study such surface by adsorption of some volatile amines and probably by using Raman spectroscopy methods, but it's a bit sophisticated I guess.
I would suggest to try using contact angle measurements:
http://gmwgroup.harvard.edu/pubs/pdf/301.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a158596.pdf
http://www.ecf.utoronto.ca/~molly/publications/control%20of%20wettability...surface%20chemistry.pdf
http://gmwgroup.harvard.edu/pubs/pdf/260.pdf
http://144.206.159.178/ft/2957/77554/1310941.pdf
I believe that these and related publications should be reproduced in your system. I thin that a kind of "surface titaration" based on caontact angle measurements would be highyl relevant to your potential applications.
Thanks a lot! We were actually planning to perform contact angle measurements as a separate experiment (just to determine wettability) but now I see we can gat more informaton from that.
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