polyethylene glycol MW 1000

wt%		log P (dynes/cm^2)

5.0		6.07
10.0		6.61
15.0		6.82
20.0		7.08
25.0		7.34
30.0		7.46
35.0		7.55
40.0		7.65
45.0		7.79
50.0		7.89
55.0		7.93
60.0		7.95	
2.5		6.11
5.0		6.27
10.0		6.54
15.0		6.86
20.0		7.05
25.0		7.26
30.0		7.43
35.0		7.58

An equation that fits this data is the following.

log P = a + b * (wt%) ^ c

where a = 4.87, b = 0.80 and c = 0.34

Note that it should be applied only over the range of pressures measured.