Variation of the duration of the isotherm process was also used to determine the speed of the liquid-to-rotator transition. Figure shows the relative transition enthalpies obtained from integrating the heat capacity on re-heating after isothermal crystallization (for different total crystallization times). These relative transition enthalpies represent the fraction of n-alkane molecules in the rotator phase at a given time. For bulk C30d, the transition enthalpies obtained from integrating the heatflow during the long isothermal crystallization steps are plotted as a reference, and show that both methods are in good agreement. In bulk both the liquid-to-rotator and rotatorto-crystal transition occur faster at lower crystallization temperatures (see also Figure ). Consequently, n-alkane diffusion coefficients should be of low relevance in this system. For C30d in DMPC, our data is not precise enough to make such a claim. However, the formation of the rotator phase appears to be a two-step process: Initial "gelation" of preorganized n-alkane chains occurs as fast as in bulk, as evidenced by the high relative transition enthalpy after only one minute of crystallization. The following slow increase in melting enthalpy suggest that additional molecules are added to the rotator-phase nuclei with time. Notably, the transition enthalpy measured in the mixture would also include some bulk alkane, as described above. By subtracting a fixed fraction of the bulk transition enthalpy at each time point, the relative transition enthalpy of only the mixed alkane can be estimated. Evidently (Figure ), assuming 20% of bulk C30d in the sample, the relative transition enthalpy still reaches a value of 0.66 after one minute, confirming that initial formation of the rotator phase is indeed very fast.