Critical unfolding temperature (Tunfolding) versus molecule length. Due to the stochastic nature of unfolding, simulation results indicate a range of possible unfolding temperatures for each length of carbyne model. The maximum and minimum of each length are plotted. For example, for n = 126 (L ≅ 170 Å), both unfolding and stable structures were observed at temperatures from 575 to 650 K (points plotted), but all simulations above 650 K unfolded, and all below 575 K remained stable. The results were fitted with a linear regression (red line), resulting in a temperature intercept of -204 ± 142 K and a slope of 4.2 ± 0.85 K Å-1 (with an associated R2 value of 0.889). The results can be associated with Equation 6. The regression can be used to delineate the folded (stable) and unfolded (unstable) states in an effective phase diagram. The 90% confidence intervals are also plotted, encapsulating all observed data points.
Cranford Nanoscale Research Letters 2013 8:490 doi:10.1186/1556-276X-8-490