polyethylene glycol MW 3000 wt% log P (dynes/cm^2) 10.0 6.26 15.0 6.61 20.0 6.84 25.0 7.07 30.0 7.28 35.0 7.46 An equation that fits this data is the following. log P = a + b * (wt%) ^ c where a = 4.42, b = 0.74 and c = 0.40 Note that it should be applied only over the range of pressures measured.