Coupling and Decoupling between Stickers and Backbones in Associating Polymers with Terminally Functionalized Side Chains,Macromolecules

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Coupling and Decoupling between Stickers and Backbones in Associating Polymers with Terminally Functionalized Side Chains
Macromolecules ( IF 5.1 ) Pub Date : 2024-08-15 , DOI: 10.1021/acs.macromol.4c00983
Chien-Hua Tu ₁ , Eli J. Fastow ₁ , Roshni John Chethalen ₂ , George V. Papamokos ₃ , E. Bryan Coughlin ₂ , Karen I. Winey _{1,

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Affiliation

Associating polymers have recently attracted tremendous attention as self-healing polymers due to the dynamic reversibility of sticker association–dissociation processes. These sticker dynamics inevitably slow significantly as segmental dynamics decelerate below the glass transition temperature that limits the operational temperatures of associating polymers. Using broadband dielectric spectroscopy on a new set of associating polymers composed side chains of various lengths and terminal carboxylic-acid sticker functionality, we discovered an unexpected decoupling near the glass transition (T_g) between the slower backbone and fast sticker motions. These two motions have distinct activation energies for the motion of the sulfur linkage adjacent to the backbone (∼22 to 26 kJ/mol) and the carboxylic acid groups (∼5 to 8 kJ/mol). A second decoupling appears in the polymer with the longest side chain length at T_g – 20 K, reflecting the dynamics of various carboxylic acid binding configurations. Our findings open the door to design associating polymers with the capability of sticker association/dissociation at low temperatures.

中文翻译：

末端官能化侧链缔合聚合物中贴纸和主链之间的偶联和解偶联

由于贴纸缔合-解离过程的动态可逆性，缔合聚合物作为自修复聚合物最近引起了极大的关注。当链段动力学减速到玻璃化转变温度以下时，这些贴纸动力学不可避免地显着减慢，玻璃化转变温度限制了缔合聚合物的操作温度。对一组由不同长度的侧链和末端羧酸贴纸功能组成的新型缔合聚合物使用宽带介电光谱，我们发现较慢的主链和快速的贴纸运动之间在玻璃化转变（ T _g ）附近出现意外的解耦。对于与主链相邻的硫键（~22至26 kJ/mol）和羧酸基团（~5至8 kJ/mol）的运动，这两种运动具有不同的活化能。在Tg – 20 K 时，第二次解偶联出现在具有最长侧链长度_的聚合物中，反映了各种羧酸结合构型的动态。我们的研究结果为设计具有低温下贴纸缔合/解离能力的缔合聚合物打开了大门。

更新日期：2024-08-15

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