Crystal engineering of nonporous organic solids for methane sorption

The low density polymorph of the well-known host p-tertbutylcalix[4]arene absorbs more methane than p-tert-pentylcalix[4]arene at room temperature and 1 atm pressure, but the order of absorption is reversed at 38 atm with p-tertpentylcalix[4]arene absorbing more.