Counterintuitive influence of microscopic chirality on helical order in polymers

Studies of copolymers of chiral and achiral units forming a helical array correlate to statistical physical predictions of the influence of the chiral units on the helical sense taken by the array. In the absence of conflict among the chiral units for helical sense control, the sergeants and soldiers experiment, a larger chiral bias leads to increased control. However, when conflict exists among the chiral units for helical sense control, the majority rule experiment, a larger chiral bias leads to decreased control of the helical sense and therefore a smaller optical activity. Changing the achiral units in the majority rule experiment can change the nature of the statistical physics between statistical and thermal randomness. In general, the experiments quantitatively demonstrate that the effect of chirality is not an intrinsic property of the chiral moiety but rather depends on the molecular environment. Copyright (C) 2004 John Wiley Sons, Ltd.