Department of Physics, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
School of Physical Sciences, University of Kent, Canterbury, CT2 7NH, UK
Lab-Tools Ltd., Kent Enterprise Hub, University of Kent at Canterbury, Canterbury, Kent. CT2 7NJ. U.K
Neutron diffraction technique used to study structural characterization of water/ice in mesoporous SBA-15 silica with 86Å nanopore diameter. Different filling factors of the silica pores, considered over a wide temperature range. Neutron diffraction data for the almost-filled case with filling factor of 0.95 that undergoes a temperature change of 300-100K, shows a main asymmetric triplet peak ~1.74Å-1. Using five symmetric functions, we found an excellent fit with the whole range of data sets for the triplet. Interestingly each of these functions directly linked to the position of different ice components and show systematic variation of peak parameters. As a complementary experiment, data analysis of the partially-filled cases with filling factor of 0.6 (300-130K) and 0.4 (300-100K), show characteristics that markedly differ from those of the filling factor 0.95. The nucleation temperature for all cases is reduced and different ice structures along with their temporal order have been detected for confined water. Further investigations confirm that for the different filling factors, there are different amount of hexagonal, cubic and the disordered ice component. Surprisingly, data analysis proved the reversibility of the whole nucleation process, although the formation/melting of the ice in the main body of the pore show the expected hysteresis.