Abstract
The ESR line-shape of the negative spin probe, 2,2,5,5-tetramethyl-pyrroline-1-oxyl-3-carboxylate in aqueous solution adsorbed on silica gels of pore size ranging from 4 to 10 nm was analysed in order to investigate the mobility of water outside the silica surface in different time domains for the motion. The nitroxide radicals mainly reside in the intermediate and middle regions of the pores, thus giving rise to slow motion and broad undetectable absorptions as the temperature decreases. Both correlation times and activation energies for the motion indicate a progressive trend of the water properties towards those of unadsorbed water. The results obtained in this work are compared with those previously obtained with neutral and positive radicals and with transition metal ions.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
