The relationship between micro- and mesoporous substructures upon removal of colloidal silica from porous glasses subjected to alkaline treatment

Porous glasses as a host of luminescent materials, their applications and site selective determination

“…Pore size in porous glass (host material) in maximum of distribution, count from PALS measurements is equal to 18.6 nm. Previous investigations made using the most common technique, liquid nitrogen adsorption/desorption (LN), allowed to determine the size of material used here of 24 nm [31]. The pore diameter determined from LN is higher than that found from PALS while maximal number of pores seen by SEM belonged to the range 9-17 nm (Fig.…”

Electrokinetic Properties of Mesoporous Vitreous Membranes Doped by Silver-Silver Halides

“…For microporous membranes ( Figure 10 ), absolute values of zeta-potential increase at solution concentration 10 −3 –10 −1 M, whereas at C < 10 −3 M either decrease or are constant. The observed regularities can be associated both with the shortcomings of the theory of electrokinetic phenomena for small electrokinetic radii kr and with the changes in the morphology of the pore space of MIP membranes containing significant amounts of secondary silica [ 37 , 40 ]. The swelling degree of the secondary silica increases with dilution to the greater degree, the more counterion is hydrated (in our case, the sodium counterion), which leads to a displacement of the slipping plane further from the pore channel surface and, therefore, to a decrease in |ζ| values.…”

“…So-called microporous (MIP) glasses (according S.P. Zhdanov terminology [ 35 ]) were obtained according to the standard procedure [ 36 , 37 , 38 ] from the monolithic two-phase alkaline borosilicate glasses with a two-frame structure of 8V-NT composition (wt %): 6.74 Na 2 O—20.52 B 2 O 3 —0.15 Al 2 O 3 —72.59 SiO 2 [ 36 ] through chemically etching (leaching) in 3 M HNO 3 aqueous solutions at boiling. Next, the leached samples were washed with distilled water and dried in an air drying box at 120 °C for 1 h [ 39 ].…”

“…Next, the leached samples were washed with distilled water and dried in an air drying box at 120 °C for 1 h [ 39 ]. As a result, porous MIP glasses [ 37 , 40 ] were obtained.…”

“…Macroporous (MAP) glasses were prepared from MIP ones by additional treatment in 0.5 M KOH solution at 20 °C, with subsequent washing in distilled water and air drying at 120 °C for 1 h. Secondary silica is removed from the pore space [ 37 ] of the MIP glasses during their alkali treatment as a result the average pore size increases [ 37 , 38 ]. We marked our membranes as MIP and MAP according to their preparation technique.…”