data files are named as follow:
date of measurement_type of surfactant_ concentration of surfactant_ pH of measurement_number of measurement

surfactants:
OA	Oleic acid
NaOL	Sodium oleate
OP	Octyl punicine
NP 	Nonyl punicine
DP	Decyl punicine
UDP	Undecyl punicine
HDP	Heptadecyl punicine