Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Department of Surgery, The Center for Engineering in Medicine (CEM), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
J Chem Phys. 2022 Mar 21;156(11):114902. doi: 10.1063/5.0078937.
Many macromolecules of biological and technological interest are both chiral and semi-flexible. DNA and collagen are good examples. Such molecules often form chiral nematic (or cholesteric) phases, as is well-documented in collagen and chitin. This work presents a method for studying cholesteric phases in the highly successful self-consistent field theory of worm-like chains, offering a new way of studying many biologically relevant molecules. The method involves an effective Hamiltonian with a chiral term inspired by the Oseen-Frank (OF) model of liquid crystals. This method is then used to examine the formation of cholesteric phases in chiral-nematic worm-like chains as a function of polymer flexibility, as well as the optimal cholesteric pitch and distribution of polymer segment orientations. Our approach not only allows for the determination of the isotropic-cholesteric transition and segment distributions, beyond what the OF model promises, but also explicitly incorporates polymer flexibility into the study of the cholesteric phase, offering a more complete understanding of the behavior of semiflexible chiral-nematic polymers.
许多具有生物和技术意义的大分子既具有手性又具有半柔性。DNA 和胶原蛋白就是很好的例子。此类分子通常形成手性向列(或胆甾型)相,这在胶原蛋白和几丁质中已有充分记载。这项工作提出了一种在手性向列蠕虫链的自洽场理论中研究胆甾型相的方法,为研究许多与生物学相关的分子提供了一种新方法。该方法涉及一个具有手性项的有效哈密顿量,该手性项受液晶的 Oseen-Frank(OF)模型启发。然后,该方法用于研究手性向列蠕虫链中胆甾型相的形成,作为聚合物柔性的函数,以及最佳胆甾型螺距和聚合物段取向的分布。我们的方法不仅可以确定各向同性-胆甾型转变和段分布,超出了 OF 模型的承诺,而且还将聚合物柔性明确纳入胆甾型相的研究中,从而更全面地了解半柔性手性向列聚合物的行为。