Conclusions
Metropolis Monte Carlo simulations showed that the number of gauche bonds is effectively zero for TC hydrocarbon chains at a temperature of 30°. This means that, at that temperature, TC molecules are fully extended and effectively rigid.
Using the experimental q-value for the Bragg peak, a tilted angle of 27° was obtained, which seems to be in essential agreement with one of the local free energy minimum, the predicted value of 33° from the paper Peyronel et al. (in review) The disagreement between 27° and 33° is, perhaps, not surprising when one considers the crudity of the model. This result, however, justifies the concept of “locked-in” states and supports the results obtained using the MMC method in which the TC and BL chains are rigidly extended.
Similar conclusions can be said for the BL molecule, except that for BL, the tilt angle obtained using the MMC and the experimental value was ~40°. 40° was not one of the computed local minimum. This also is not surprising because of the effects of electrostatic interactions dealt with by Peyronel et al. (in review). There we compared the strengths of the repulsive electrostatic interactions and the attractive dispersion energies and concluded that it was not possible within the context of the hydrocarbon chain “lock-in” model to easily deduce a unique tilt angle. In the case of BL, MMC computation would be necessary, but that is not the purpose of this paper.
The theory of chain tilting reported by Peyonel et al. (in review) could also apply to other symmetric monolayer systems in which this phenomenon can be observed. Chain tilting alone, however, should not be applied to systems which contain asymmetric layering or bilayers, in which twists (gauche bonds) may be more appropriate to explain these and other kinds of phenomena.
These results should help food scientists simulate and predict, by using these techniques, the average length of a bilayer of possible oleogelators.
Acknowledgements: This project was supported by the Utah Agricultural Experiment Station, Utah State University and approved as paper number 9645. Authors would like to thank Utah State University, the University of Guelph, St. Francis Xavier University. DAP likes to acknowledge NSERC of Canada (grant # R0178050).
Conflict of interest: Authors declare no conflict of interest.
Authors contribution: Dr. Silvana Martini, Dr. David Pink, and Dr. Fernanda Peyronel conceived the idea and provided insight into the project. Dr. Silvana Martini and Dr. Pink provided funding and wrote parts of the manuscript. Mr. Joseph Cooney designed, coded, and tested the simulation, gathered and presented data, and wrote the manuscript. All authors reviewed the manuscript before submission.