[Lilly5670]

How does the retardation factor (Rf) relate to the degree of interaction between the substance and the mobile phase?

couldn't figure it out exactly when reading my book but I'm guessing Rf decreases with decreasing interactions? --This is for Organic chemistry lab

[Babcock_Hall]

My opinions only, but I think it can be misleading to focus on the interactions between the substance (analyte) and the mobile phase.  Misleading in the sense that it is possible to make wrong predictions about how R_f changes with changes in polarities.

It is better to focus on the interactions between the substance and the stationary phase versus the solvent and the stationary phase when predicting how R_f values change with changes in the polarity of the solvent or the polarity of the analyte.  In other words, I like to think of the situation as being a competition between solvent vs. analyte for binding to the stationary phase.  When the analyte wins, it moves slowly up the TLC plate.