A water-in-water(W/W)emulsion consists of droplets formed by the spontaneous liquid-liquid separation of two immiscible aqueous phases.The inherent properties of the W/W interfaces,low or ultralowinterfacial tension(...A water-in-water(W/W)emulsion consists of droplets formed by the spontaneous liquid-liquid separation of two immiscible aqueous phases.The inherent properties of the W/W interfaces,low or ultralowinterfacial tension(γ_(W/W)=1-1000μN/m)and a large thickness of several nanometers,beget the poor inherent stability of emulsions.Herein,we report a nanofibril emulsifier having Schiff base reactivity to generate a W/W emulsion.The W/W emulsion has superior stability(stable>6 months)because collagen nanofibrils,acting as a stabilizer of W/W emulsions,can simultaneously satisfy the requirements of sizeandoverall coverage ratio of the phase interfaces.W/Wemulsions having γ_(W/W)∼10μN/m were used as synthetic synovial fluids,showing superior lubrication performance with a coefficient of friction in the range of 0.003-0.011,which has been demonstrated to be suitable for joint lubrication.An intraarticular injection assessment further confirmed this protective effect on articular cartilage in vivo.Our study reveals the mechanism of emulsion stabilization and opens up the possibility of osteoarthritis(OA)treatment using the biolubrication effects of W/W emulsions for lubricated artificial implant surfaces.展开更多
The hydration lubrication paradigm,whereby hydration layers are both strongly held by the charges they surround,and so can support large pressures without being squeezed out,and at the same time remain very rapidly re...The hydration lubrication paradigm,whereby hydration layers are both strongly held by the charges they surround,and so can support large pressures without being squeezed out,and at the same time remain very rapidly relaxing and so have a fluid response to shear,provides a framework for understanding,controlling,and designing very efficient boundary lubrication systems in aqueous and biological media.This review discusses the properties of confined water,which-unlike organic solvents-retains its fluidity down to molecularly thin films.It then describes lubrication by hydrated ions trapped between charged surfaces,and by other hydrated boundary species including charged and zwitterionic polymer brushes,surfactant monolayers,liposomes,and biological macromolecules implicated in synovial joint lubrication.Finally,challenges and prospects for future development of this new boundary lubrication approach are considered.展开更多
基金the National Natural Science Foundation of China(grant nos.22032003,22072073,and 22002072)the Natural Science Foundation of Shandong Province(nos.ZR2018 ZA0547 and ZR2020QB061)+1 种基金Australian Research Council(ARC)DP 190103455the fellowship of China Postdoctoral Science Foundation(no.2020M672043).
文摘A water-in-water(W/W)emulsion consists of droplets formed by the spontaneous liquid-liquid separation of two immiscible aqueous phases.The inherent properties of the W/W interfaces,low or ultralowinterfacial tension(γ_(W/W)=1-1000μN/m)and a large thickness of several nanometers,beget the poor inherent stability of emulsions.Herein,we report a nanofibril emulsifier having Schiff base reactivity to generate a W/W emulsion.The W/W emulsion has superior stability(stable>6 months)because collagen nanofibrils,acting as a stabilizer of W/W emulsions,can simultaneously satisfy the requirements of sizeandoverall coverage ratio of the phase interfaces.W/Wemulsions having γ_(W/W)∼10μN/m were used as synthetic synovial fluids,showing superior lubrication performance with a coefficient of friction in the range of 0.003-0.011,which has been demonstrated to be suitable for joint lubrication.An intraarticular injection assessment further confirmed this protective effect on articular cartilage in vivo.Our study reveals the mechanism of emulsion stabilization and opens up the possibility of osteoarthritis(OA)treatment using the biolubrication effects of W/W emulsions for lubricated artificial implant surfaces.
文摘The hydration lubrication paradigm,whereby hydration layers are both strongly held by the charges they surround,and so can support large pressures without being squeezed out,and at the same time remain very rapidly relaxing and so have a fluid response to shear,provides a framework for understanding,controlling,and designing very efficient boundary lubrication systems in aqueous and biological media.This review discusses the properties of confined water,which-unlike organic solvents-retains its fluidity down to molecularly thin films.It then describes lubrication by hydrated ions trapped between charged surfaces,and by other hydrated boundary species including charged and zwitterionic polymer brushes,surfactant monolayers,liposomes,and biological macromolecules implicated in synovial joint lubrication.Finally,challenges and prospects for future development of this new boundary lubrication approach are considered.
