Surface tension of cavities and Tolman's length in n-alkanes. A positron study

► Surface tension in cavities produced by Ps in alkanes is larger than in flat surface. ► Absolute value of Tolman's length rises with temperature. ► Ortho-Ps lifetime near the melting point is identical for all liquid alkanes. ► No change of ortho-Ps lifetime at the transition liquid-rotator phase for n > 24.