Low-friction lubricant formulations are urgently needed to improve the energy efficiency of machines. Here, we show that blending 1-dodecanol with a hydrocarbon oil improves lubrication in non-conformal sliding/rolling contacts by simultaneously increasing hydrodynamic film thickness and reducing viscous friction. This is due to pressure-induced polymorphic phase transformations in the 1-dodecanol molecules after they flow through the film thickness-determining inlet and reach the load-supporting zone. At relatively low pressures, 1-dodecanol forms a lamellar hexagonal solid polymorph that gives durable superlubricity then, at higher pressures, it forms an orthorhombic polymorph. Both polymorphs cause anomalously low friction when blended into various hydrocarbon base oils over a wide range of speed, pressure, and shear rate conditions representative of rolling bearing and gear contacts. By breaking the ubiquitous trade-off between friction and film thickness, and enabling superlubricity, these blends pave the way for considerable energy efficiency improvements in widespread lubricated contacts.

中文翻译：

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打破油膜厚度和粘性摩擦之间的权衡 - 高压接触中含 n-alcohol 的润滑剂


迫切需要低摩擦润滑剂配方来提高机器的能源效率。在这里，我们表明，将 1-十二醇与烃类油混合，通过同时增加流体动力膜厚度和减少粘性摩擦来改善非保形滑动/滚动接触中的润滑。这是由于 1-十二醇分子在流经决定薄膜厚度的入口并到达负载支撑区后，压力诱导的多晶型相变。在相对较低的压力下，1-十二醇形成层状六方固体晶型物，提供持久的超润滑性，然后在较高压力下形成正交多晶型物。当混合到各种碳氢化合物基础油中时，这两种多晶型物在代表滚动轴承和齿轮接触的广泛速度、压力和剪切速率条件下都会产生异常低的摩擦。通过打破摩擦和油膜厚度之间无处不在的权衡，并实现超润滑性，这些混合物为广泛润滑触点的能源效率显著提高铺平了道路。