发表机构
Georgia Institute of Technology; Colorado School of Mines; Multiscale Technologies Inc.; United States Naval Academy; United States Naval Research Laboratory（佐治亚理工学院; 科罗拉多矿业学院; Multiscale Technologies 公司; 美国海军学院; 美国海军研究实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究针对PFAS螺旋度缺乏定量度量的问题，提出含三类统计描述符的数据驱动框架，经多类PFAS验证可用于其环境归趋预测模型。
AI 中文摘要
全氟和多氟烷基物质（PFAS）在环境中极强的持久性源于其三维分子构象。全氟烷基链因涉及难降解C-F键的超共轭作用而形成的螺旋扭转决定了其抗降解能力，但目前仍缺乏定量的、连续的螺旋度度量标准。本文提出一种数据驱动框架，通过三种统计描述符量化主链螺旋度：空态（二元占据）空间自相关、局部主链主成分分析及持久同调。我们进一步针对几何二面角基准和密度泛函理论（DFT）计算的振动圆二色（VCD）光谱验证了每种统计描述符。该框架最初建立在全氟羧酸（FC2至FC16）及其氢化类似物的同系物系列上，随后扩展至全氟磺酸、氟调聚醇、多氟烷基己酸类似物，以及更长链的全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）类似物。针对全氟羧酸建立了螺旋度的统计、几何和光谱定义间的一致性，并将其扩展至结构不同的亚家族，包括含不同氟含量的PFOA类似物及全氟磺酸，证明这些描述符对头部基团化学和氟取代模式的变化具有鲁棒性。该框架提供了一套与化学无关的工具集，可将主链构象纳入PFAS环境归趋和降解反应性的预测模型中。
英文摘要
The extreme persistence of per- and polyfluoroalkyl substances (PFAS) in the environment is rooted in their three-dimensional molecular conformation. The helical twist adopted by perfluoroalkyl chains due to hyperconjugation involving their recalcitrant C-F bonds governs their resistance to degradation, yet a quantitative, continuous metric for helicity has remained absent. Here we introduce a data-driven framework that quantifies backbone helicity using three statistical descriptors: void-state (binary occupancy) spatial autocorrelations, local backbone principal component analysis, and persistent homology. We further validate each statistical descriptor against geometric dihedral benchmarks and DFT-calculated Vibrational Circular Dichroism (VCD) spectra. The framework is initially established on a homologous series of perfluorocarboxylic acids (FC2 through FC16) and their hydrogenated analogues, then extended across perfluorosulfonic acids, fluorotelomer alcohols, polyfluoroalkyl hexanoic acid analogues, and longer-chain PFOA and PFOS analogues. Agreement between statistical, geometric, and spectroscopic definitions of helicity is established for PFCAs and extended to structurally distinct subfamilies, including PFOA analogues of varying fluorine content and perfluorosulfonic acids, demonstrating that the descriptors are robust to changes in headgroup chemistry and fluorine substitution pattern. The framework provides a chemistry-agnostic toolset for incorporating backbone conformation into predictive models of PFAS environmental fate and degradation reactivity.
