Molecules with a TEMPO-based head group as high-performance organic friction modifiers
Molecules with a TEMPO-based head group as high-performance organic friction modifiers
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具有 TEMPO 头基的分子作为高性能有机摩擦改进剂
DOI：
10.1007/s40544-022-0610-0
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发表时间：
2022
期刊：
影响因子：
6.8
通讯作者：
Azuma Naoki
中科院分区：
文献类型：
--
作者：
Hou Jinchi;Tsukamoto Masaki;Hor Seanghai;Chen Xingyu;Yang Juntao;Zhang Hedong;Koga Nobuaki;Yasuda Koji;Fukuzawa Kenji;Itoh Shintaro;Azuma Naoki
添加到润滑油中的高性能有机摩擦改进剂(OFM)对于减少能量损失和碳足迹至关重要。为了建立一类新的OFM，我们测量了N-(2，2，6，6-tetramethyl-1-oxyl-4-piperidinyl)dodecaneamide的摩擦磨损性能，称为C12酰胺-TEMPO。通过实验和量子力学(QM)计算研究了它的头基化学，其特征是一个刚性的六元环夹在一个酰胺基和一个末端的氧自由基之间。测试结果表明，C12酰胺-TEMPO的性能优于传统的单油酸甘油酯和硬脂酸，特别是在承载能力、减磨性和摩擦稳定性方面。C_(12)酰胺-TEMPO的减摩减磨效果也大大优于C_(12)酯-TEMPO和C_(12)氨基-TEMPO，其中酯基和氨基取代了酰胺基，突出了酰胺基的关键作用。QM计算结果表明，与C12Ester-Tempo、C12Amino-Tempo以及GMO和硬脂酸的常规OMMS相比，C12酰胺-TEMPO可以在氧化铁表面形成有效的边界膜，具有独特的双层结构：由于酰胺氧和自由基与氧化铁表面的化学作用，形成了较强的表面吸附层，而由于酰胺氢与自由基间或酰胺氢与氧之间的层间氢键，形成了上层。此外，两层中的每一层中的层内氢键也是可能的。我们认为，除了强烈的表面吸附外，层间和层内氢键还通过增强结合强度增加了边界膜的强度，从而导致了C12酰胺-TEMPO的高摩擦学性能。本研究的发现有望为优化OFMS的分子设计提供新的线索。
High-performance organic friction modifiers (OFMs) added to lubricating oils are crucial for reducing energy loss and carbon footprint. To establish a new class of OFMs, we measured the friction and wear properties of N-(2,2,6,6-tetramethyl-1-oxyl-4-piperidinyl)dodecaneamide referred to as C12Amide-TEMPO. The effect of its head group chemistry, which is characterized by a rigid six-membered ring sandwiched by an amide group and a terminal free oxygen radical, was also investigated with both experiments and quantum mechanical (QM) calculations. The measurement results show that C12Amide-TEMPO outperforms the conventional OFMs of glyceryl monooleate (GMO) and stearic acid, particularly for load-carrying capacity, wear reduction, and stability of friction over time. The friction and wear reduction effect of C12Amide-TEMPO is also greatly superior to those of C12Ester-TEMPO and C12Amino-TEMPO, in which ester and amino groups replace the amide group, highlighting the critical role of the amide group. The QM calculation results suggest that, in contrast to C12Ester-TEMPO, C12Amino-TEMPO, and the conventional OFMs of GMO and stearic acid, C12Amide-TEMPO can form effective boundary films on iron oxide surfaces with a unique double-layer structure: a strong surface adsorption layer owing to the chemical interactions of the amide oxygen and free radical with iron oxide surfaces, and an upper layer owing to the interlayer hydrogen-bonding between the amide hydrogen and free radical or between the amide hydrogen and oxygen. Moreover, the intralayer hydrogen-bonding in each of the two layers is also possible. We suggest that in addition to strong surface adsorption, the interlayer and intralayer hydrogen-bonding also increases the strength of the boundary films by enhancing the cohesion strength, thereby resulting in the high tribological performance of C12Amide-TEMPO. The findings in this study are expected to provide new hints for the optimal molecular design of OFMs.
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影响因子：
3.2
作者：
A. Pominov;Johannes Müller-Hillebrand;Johannes Träg;D. Zahn
通讯作者：
A. Pominov;Johannes Müller-Hillebrand;Johannes Träg;D. Zahn
关于润滑的讨论
DOI：
10.1088/1478-7814/32/1/339
发表时间：
1919
期刊：
--
影响因子：
--
作者：
R. M. Deeley
通讯作者：
R. M. Deeley
溶解的长链硝基氧的电子自旋共振
DOI：
10.1021/j100858a030
发表时间：
1968
期刊：
The Journal of Physical Chemistry
影响因子：
--
作者：
A. Waggoner;A. Keith;O. Griffith
通讯作者：
O. Griffith
影响因子：
3.9
作者：
Ewen, James P.;Gattinoni, Chiara;Dini, Daniele
通讯作者：
Dini, Daniele
有机摩擦改进剂行为的基础知识
DOI：
--
发表时间：
2012
期刊：
影响因子：
--
作者：
S. Campen
通讯作者：
S. Campen