Synthetic polymers have widespread applications in daily life and advanced materials applications. Making polymers efficiently and controllably is highly desired, for which modulating intramolecular and intermolecular interactions have been an effective approach. Recent real-time single-polymer growth studies uncovered nonequilibrium conformational entanglements that form stochastically under living polymerization conditions and which appear to plausibly play key roles in controlling the polymerization kinetics and dispersion. Here, using magnetic tweezers measurements, we study the real-time polymerization dynamics of single polynorbornene-based polymers in which we systematically tune the hydrogen-bonding interactions by titrating the OH content in the monomers and the formed polymers during ring opening metathesis polymerization. Using norbornenes with and without a hydroxyl group and a nonreactive monomer analogue, we show that intrachain and intermolecular hydrogen bonding compete, and both alter the microscopic properties of the nonequilibrium entanglements, leading to surprising multiphasic dependences of polymerization dynamics on the polymer’s OH content. We further formulate a simple model to rationalize quantitatively the observed multiphasic behaviors by considering the different scaling relations of intrachain and intermolecular hydrogen bonding on the OH content. These results provide insights into the interconnected roles of intra-/intermolecular interactions, polymer chain conformations, and free monomers in solution in affecting polymerization kinetics and dispersion, and point to new opportunities in manipulating polymerization reactions.

中文翻译：

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通过构象纠缠中的氢键调节单聚合物生长

合成聚合物在日常生活和先进材料应用中有着广泛的应用。非常需要有效且可控地制造聚合物，为此调节分子内和分子间相互作用是一种有效的方法。最近的实时单聚合物生长研究揭示了非平衡构象纠缠，这些纠缠在活性聚合条件下随机形成，并且似乎在控制聚合动力学和分散中起关键作用。在这里，使用磁性镊子测量，我们研究了基于单一聚降冰片烯的聚合物的实时聚合动力学，其中我们通过滴定开环复分解聚合过程中单体和形成的聚合物中的 OH 含量来系统地调节氢键相互作用。使用带有和不带有羟基的降冰片烯和非反应性单体类似物，我们表明链内和分子间氢键竞争，并且都改变了非平衡缠结的微观性质，导致聚合动力学对聚合物的 OH 含量的令人惊讶的多相依赖性。我们进一步制定了一个简单的模型，通过考虑链内和分子间氢键对 OH 含量的不同比例关系，定量地合理化观察到的多相行为。这些结果提供了对分子内/分子间相互作用、聚合物链构象和溶液中游离单体在影响聚合动力学和分散中的相互关联作用的见解，并指出了操纵聚合反应的新机会。