Effect of synthesis temperature on the ordered pore structure in mesoporous silica studied by positron annihilation spectroscopy

- o-Ps lifetimes corresponding to micro- and mesopores are observed.
- The mesopores show ordered structure in the sample synthesized around 150 °C.
- A higher synthetic temperature at 180 °C leads to collapse of the ordered pores.
- The pore size estimated by positron is in agreement with gas adsorption result.