Light-controlled friction realized by a photorheological fluid

Tang, Shuangxi; Li, Shayu; Zhu, Shirley; Ma, Liran; Tian, Yu

doi:10.1016/j.triboint.2022.107914

Cited by 7 publications

(1 citation statement)

References 46 publications

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“…Although stimuli-responsive polymer materials, which are readily offering physicochemical properties varying in response to the stimuli, can be considered promising candidates for ILM, there are rare reports on the ILM based on stimuli-responsive materials because realizing the matching between responsive and desired tribological behavior remains a challenge. At present, the research based on stimuli-responsive polymer ILM mainly focuses on polymer brushes [11,12], microgels, biomimetic lubricating materials based on polymer [13], hydrogels, or ionic gels [14][15][16]. However, the feature of the soft materials constrained the practical application, such as poor mechanical properties, complex structures, and additional lubricants are required in some cases.…”

Section: Introductionmentioning

confidence: 99%

Thermal Tunable Tribological Behavior of Shape Memory Biphenyl Epoxy Resin

et al. 2023

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Although polymer-based self-lubricating materials have rapidly developed recently, intelligent lubricating materials with self-adaptable lubrication with external conditions changing are highly demanded, especially for harsh conditions. Herein, a shape memory epoxy resin based on the biphenyl units (BPEP) with tunable tribological behavior was systematically studied. X-ray diffraction (XRD), field emission scanning electron microscope (SEM), laser confocal three-dimensional profiler, and optical microscope were applied to analyze the friction and wear mechanism. Due to the presence of the specific biphenyl structural units, which could be performed a switching phase between crystalline and amorphous, that allows the self-assembly of the polymer chain under π–π interaction. As a result, the improving mechanical properties enable the BPEP to perform outstanding self-lubricating in a wide temperature range, and the friction coefficient (COF) can be tuned in a wide range of 0.10~0.175 by adjusting the temperature. The shape memory effect of the polymer refers to modulus changing and heat conversion during the shape morphing, and a thermal tunable tribological was observed based on the physicochemical properties varying of polymer with temperature changing. The shape memory effect of BPEPs drives the wear self-compensation so that a low wear rate (6.94 × 10−5 mm3 N−1 m−1) at 110 °C was obtained. The superb lubricating properties of this BPEP could broaden the application scope of shape memory polymers in the field of intelligent lubricating materials, and it is expected to guide future studies on the thermal regulating of tribological behavior.

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Section: Introductionmentioning

confidence: 99%

Thermal Tunable Tribological Behavior of Shape Memory Biphenyl Epoxy Resin

et al. 2023

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Illuminating Pathways to Dynamic Nanotribology: Light‐Mediated Active Control of Interfacial Friction with Nanosuspensions

Leidens,

Michels,

Machado

et al. 2024

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Active control of nanotribological properties is a challenge. Materials responsive to external stimuli may catalyze this paradigm shift. Recently, the nanofriction of a thin film is modulated by light, ushering in phototribology. This frontier is expanded here, by investigating photoactive nanoparticles in lubricants to confer similar functionality to passive surfaces. Quartz‐crystal microbalance (QCM) is employed to assess the phototribological behavior of aqueous suspensions of titanium dioxide nanoparticles. A comparison of dark and illuminated conditions provides the first demonstration of tuning the interfacial friction in solid‐nanosuspension interfaces by light. Cyclic tests reveal reversible transitions between higher (dark) and lower friction (illuminated) regimes. These transitions are underpinned by transient states with surface charge variations, as confirmed by Zeta potential measurements. The accumulated surface charge increases repulsion within the system and favors sliding. Upon cessation of illumination, the system returns to its prior equilibrium state. These findings impact not only nanotribology but nanofluidics and nanorheology. Furthermore, the results underscore the need to consider light‐induced effects in other scenarios, including the calculation of activity coefficients of photoactive suspensions. This multifaceted study introduces a new dimension to in operando frictional tuning, beckoning a myriad of applications and fundamental insights at the nanoscale.

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