Design And Interfacial Lubrication Of Choline Proline Derivatives Ionic Liquids And Gels

Its unique structure and micro interface morphology make the human joint is an important biological friction system that is also remarkably excellent durability,high adaptability,and self-healing performance.Human articular cartilage’s superior lubrication performance is inextricably linked to its adaptive multi-mode lubrication model.In constrast to the conventional lubricating materials,the research of biological lubricating materials not only needs to obtain a low friction coefficient but also needs to consider the problem of biocompatibility.In short,it is still of great significance to apply advanced scientific and technological means to study the microstructure and mechanism of life,combine the traditional tribology theory with emerging biotribology,reveal the physicochemical essence of excellent lubrication characteristics in the biological lubrication systems,and study and design biomimetic interface lubrication materials with excellent biocompatibility and lubricity.Ionic liquids have excellent stability and lubricating properties.The preparation of ionic liquid gels with excellent lubricating properties by introducing gelation component,designing ionic liquid structures or introducing unsaturated carbon bonds is a hotspot in the field of lubricating materials research.Choline widely exists in animals and plants and is an important part of the biomembrane.Amino acids are the raw materials for protein synthesis.They have good biocompatibility and strong molecular designability.Lubrication and biocompatibility are two apparent benefits of choline amino acid ionic liquids.The research on bionic artificial articular cartilage lubricating materials and biological lubrication mechanisms with exceptionally low friction coefficient and wear rate and extended service life has always been one of the most valuable and attractive topics in biotribology.Starting from the lubrication mechanism of human joints and combined with the interaction mechanism between molecules,lubrication materials in different states were prepared based on choline and proline derivatives.The paper consists of the following four parts:1.Firstly,amphiphilic arbutin derivatives were synthesized.The derivatives can self-assemble to form micelle or vesicle structure in an aqueous solution through a hydrogen bond,hydrophilic hydrophobic and other non-covalent interactions,and form a friction film structure with high lubrication performance at the friction interface,which has excellent lubrication performance.The adsorption behavior of amphiphilic derivatives of natural arbutin at friction interface was explored by molecular dynamics simulation;Scanning electron microscopy(SEM),Transmission electron microscopy(TEM),Time-of-Flight Secondary Ion Mass Spectrometry(TOF-SIMS),and X-ray photoelectron spectroscopy(XPS)were used to confirm that arbutin derivatives can be assembled into lubricating films with high friction reduction and wear resistance at the friction interface.An additional benefit of arbutin derivatives have excellent anti-Staphylococcus aureus properties and biocompatibility.This section of the work proposes a novel selection and preparation strategy for artificial joint lubricating materials.2.Inspired by the previous work,tea saponin derivatives with excellent interfacial properties were obtained by long-chain alkyl modification with macromolecular natural tea saponin.Stable physical lubrication films with sufficient strength can be constantly formed by TSC14 and TSC16 during friction.The preparation of Choline / Acetyl-proline ionic liquids([Ch] [Ac-Pro] ILs)was carried out.It was found that TSC16 could self-assemble to form short fiber structures in [Ch][Ac-Pro] ILs,which effectively improved the rheological and tribological properties of ionic liquids.SEM,XPS analyses showed that the improvement of tribological properties depended on the joint action of TSC16/[Ch][Ac-Pro] ILs blend adsorption film and tribochemical reaction film.3.A class of choline proline derivative surface active ionic liquids(SAILs)was designed.[Ch][Pro C10] ILs and [Ch][Pro C12] ILs have a high degree of fluidity and can be self-assembled into supramolecular gels with excellent rheology properties in the presence of a small amount of water by hydrogen bonding,ionic bonding(electrostatic interaction)and hydrophobic interaction,thereby achieving the gelation of lubricating materials in the joint and effectively avoiding the loss caused by flow.The assembly mechanism of gels was studied by NMR,FTIR,POM,and TEM.Rheological properties of choline proline derivative supramolecular gel were studied by rheometer.In addition,it is discovered that the SAILs aqueous solution can form micelles or vesicle structures with excellent lubricating properties.SEM,TEM,TOF-SIMS,and XPS technologies are used to study the lubrication mechanism of supramolecular gels.The ionic liquid molecules can form a physical adsorption film on the friction surface,allowing for observation of the formation of the friction chemical reaction film.[Ch][Pro C10] ILs and [Ch][Pro C12] ILs have minimal cytotoxicity and excellent proliferation performance.They are excellent injectable bionic joint lubricating materials.4.We prepared polymerizable choline proline derivative ionic liquid(CPILs)and incorporated it into the polyacrylic acid hydrogen bonding network as a dynamic medium to prepare a series of high elastic,transparent,self-repairing,and adhesive choline amino acid derivatives polyelectrolyte hydrogel.The gel provides excellent tensile properties(the highest breaking strain is 2543%),excellent compression damping performance(maximum 50% compression stress612 k Pa),excellent self-healing ability(maximum self-healing efficiency 85.1%),and interface adhesion performance(especially on pig skin,maximum 42 k Pa)by dynamically adjusting the interfacial interaction through hydrogen bonds,ionic bonds,and other non-covalent bonds.Additionally,hydrogels with good lubricity were obtained by altering the proportion of different components of the polyelectrolyte hydrogel.The lowest average friction coefficient in water was0.106,allowing for modification of lubrication and adhesion.Because choline and proline are all substances in human body,the material has good biocompatibility.It is a potential bionic joint lubricating material.