Engineering Covalent Organic Framework Oil‐Nanocontainers for Advanced Self‐Lubricating Polymer Composites

Oil‐containing microcapsules, due to their excellent environmental adaptability and wide‐ranging applicability, are recognized as one of the critical solutions for the development of high‐end self‐lubricating bearing at present. Herein, we design a triazine‐based covalent organic framework (COF‐Tta) as nanocontainers for anchoring lubricating oil molecules and propose a universal strategy for developing high‐performance self‐lubricating polymer composites. The synthesized COF‐Tta features a high Brunauer‐Emmett‐Teller (BET) surface area of up to 861 m 2 g −1 and numerous periodic microporous channels, enabling the COF‐Tta oil‐nanocontainer to achieve a PAO6 oil loading capacity of ∼ 50%. And the COF‐Tta@Oil‐reinforced UHMWPE composite, even at a minuscule doping amount of 3%, represents a substantial reduction of over 53% in friction coefficient and over 67% in wear rate compared to pure UHMWPE in dry sliding. Combined with wear track topographies and self‐lubricating performance, it reveals that the PAO6 oils encapsulated within COF‐Tta oil‐nanocontainers can be continuously and steadily extruded onto the rubbing surfaces upon stimulation by various friction forces, thereby leading to the simultaneous reduction of both friction coefficient and wear rate. Such COF‐Tta@Oil‐reinforced strategy can also be extended to other polymer matrices, highlighting a general design idea for self‐lubricating performance enhancement.