The melting behavior of trinitrotoluene nanoconfined in controlled poreglasses

The depression of the melting temperature and heat of fusion of trinitrotoluene (TNT) confined in the nanoscale pores of controlled pore glasses (CPG) were studied by differential scanning calorimetry. 8, 12, 16, 35, and 70 nm pore size CPG were used in the experiment. Both the melting temperature and the heat of fusion of confined nanocrystals decreased with decreasing pore size, which is consistent with previous studies on other materials. When plotting the melting temperature depression as a function of reciprocal pore diameter, an excellent linear fit could be applied to the experimental data points. From the slope of this linear fit, the solid-liquid interface energy of TNT was calculated according to the Gibbs-Thomson equation and found equal to 22.1 +/- A 0.4 mJ m(-2). This is in reasonable agreement with the values calculated from the empirical Turnbull equation and the liquid layer model.