Review
Engineering, Mechanical
Meng Li, Wenbin Shi, Jun Shi, Tao Wang, Liping Shi, Xiaolei Wang
Summary: This article provides an overview of the recent research progress in modifying the wet friction characteristics of soft elastomers through surface texturing. It discusses the physical mechanisms, methods of regulating wet sliding behaviors, and the prospects and challenges of texture design for soft materials.
Article
Materials Science, Multidisciplinary
C. Oliver, D. Dalmas, J. Scheibert
Summary: The pull-off force, a direct measurement of adhesion, is influenced by various experimental parameters. This study demonstrates that shearing the contact prior to separation can affect the pull-off force. For small shear displacements, the pull-off force decreases as shear increases, while for larger shear displacements, the pull-off force remains constant at a residual value. The study also proposes a model for the critical shear displacement, based on observations of how the unloading path leading to contact separation is modified by the initial shear. These findings provide new insights into the interplay between adhesion and friction and have implications for various fields, such as tire grip, soft robotics, haptics, and animal locomotion.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Mechanical
Liguo Qin, Xiaodong Huang, Zongsheng Sun, Zeyu Ma, Fagla Jules Mawignon, Baohua Lv, Lei Shan, Guangneng Dong
Summary: The effects of surface chemistry and morphology on the stick-slip friction of poly-dimethylsiloxane (PDMS) are investigated in this study. Air plasma treatment is used to modify the surface chemistry, and a bionic shark skin texture is replicated on PDMS. The synergistic effect of the bionic shark skin texture and air plasma treatment on stick-slip friction is evaluated. The results show that both air plasma treatment and bionic texture decrease the friction force, and various stick-slip features are observed under different numbers of pendant chains, increasing the adhesion force. This study provides fundamental insights into the stick-slip behaviors of other soft materials.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Robotics
Johan Sundin, Katherine Kokmanian, Matthew K. Fu, Shervin Bagheri, Marcus Hultmark
Summary: This article introduces a new concept of a soft material flow sensor based on elastic filament velocimetry, which meets the requirements for micro air vehicles. The sensor can be manufactured using common laboratory tools, operates with a simple circuit, and allows for sensitivity and bandwidth to be varied by modifying the ribbon's geometry and material properties.
Article
Materials Science, Multidisciplinary
Masahito Ban, Ryouta Shimoda, Yuki Okigawa, Masatou Ishihara
Summary: The study shows that the presence of graphene film on PDMS significantly enhances cellular proliferation and elongation, with cells growing much faster on graphene-attached PDMS substrates. The projected surface area of the graphene film attached on PDMS strongly influences cell growth.
DIAMOND AND RELATED MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Xiuhua Zhao, Xiushuo Zhang, Ruling Chen, Haojie Lang, Yitian Peng
Summary: The friction of atomically thin graphene on a flexible substrate was tuned using a microsphere probe modified with self-assembly monolayers. The tuning was achieved by changing the elastic modulus of the substrate and the thickness of graphene. This research is significant for the design and reliability of flexible micro-devices.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Mechanical
Fitsum B. Tewelde, Tianfeng Zhou, Jia Zhou, Weijia Guo, Bin Zhao, Xiangyu Ge, Wenzhong Wang, Xiaoli Wang, Xibin Wang
Summary: This study examined the impact of asymmetric surface texturing on directional friction in a dry environment. Asymmetric micro-grooves were created on an electroless nickel phosphorous (Ni-P) plated disk using a diamond cutting process. Sliding tests were conducted in both clockwise (CW) and counter-clockwise (CCW) directions against polyether-ether-ketones (PEEK) material at various texture densities. The results indicate that asymmetric surface texturing has a significant effect on directional friction. At a texture density of 70%, the friction coefficient in the CW direction increased by 28.1% compared to the CCW direction. The lowest texture density caused a 61.3% increase in friction coefficient during CW rotation compared to the reference untextured surface.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Mechanics
Rebecca Berthold, Jessica Burgner-Kahrs, Matthias Wangenheim, Stephanie Kahms
Summary: The ability of soft robots to interact safely with the environment is a major advantage, making them suitable for various applications. However, the contact and frictional behavior of soft robots have been understudied. This work presents measurements and a representative contact model to accurately simulate the frictional contact behavior of soft material robots. The importance and influence of friction in a typical application of a soft robot are also demonstrated.
Article
Chemistry, Physical
Gang-Min Kim, Jeong-Won Lee, Sung-Jun Lee, Chang-Lae Kim
Summary: This study successfully reduced the friction coefficient between PDMS and the counter material by forming hierarchical micro/nanopatterns on the PDMS surface. Under the optimum conditions of controlling sliding speed and normal load, the patterned PDMS exhibited the lowest friction coefficient and the greatest friction reduction effect.
Article
Engineering, Mechanical
Charchit Kumar, Thomas Speck, Vincent Le Houerou
Summary: Friction on biological-like micro-structured surfaces was investigated by transferring complex surface morphologies found in plant leaves onto viscoelastic substrates using a bio-replication technique. The effects of applied normal load and sliding speed on the friction response were evaluated, with all four surfaces demonstrating a decrease in the friction coefficient with increasing normal load. Additionally, an increase in friction coefficient with rising sliding speed was observed, which was correlated with material loss factor and different friction incremental rates.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Sathishkumar Subburaj, Wei-Song Hung, Po Ting Lin
Summary: This study focuses on measuring the interfacial bonding strengths of soft composite material membranes composed of Ecoflex and PDMS. The results show that increasing the quantity of PDMS in the Ecoflex material enhances the bonding strength. This is useful for controlling the bonding strength between polymer composites in various engineering designs.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Engineering, Civil
Andrzej Dzierwa, Pawel Pawlus
Summary: The main objective of the study was to model wear of a disc subjected to dry contact with a ball in unidirectional sliding. Tribological tests were conducted, showing that wear volumes of the discs were influenced by the roughness heights of the surfaces, with a strong correlation between modeled and measured wear levels.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2021)
Article
Chemistry, Physical
Simone Lantean, Matteo Lo Preti, Lucia Beccai
Summary: This study develops a soft optical shield coating by dispersing titanium oxide particles in silicone elastomers, achieving almost full NIR shielding. The transmittance of the optical devices can be programmed by adjusting the TiO2 concentration and film thickness. The proposed material shows potential application in soft robots, as demonstrated by the soft waveguide and strain sensor.
Article
Nanoscience & Nanotechnology
Boya Li, Gao Cai, Xunzhang Li, Wenjing Sha, Xiaodong Shen, Tingwei Wang, Huaixia Zhao, Yangxin Wang, Jiaxi Cui
Summary: Researchers developed a switchable surface inspired by human fingertips, which exhibits high water sensitivity and surface variation in wet and dry states. The surface is constructed by utilizing the hygroscopicity of inorganic salt filler and 3D printing technology. Addition of fluorescent dye in the surface texture enables water-responsive fluorescent emitting, serving as a surface-tracing strategy. This switchable surface offers effective regulation of surface friction and demonstrates good anti-slip effects. The synthetic strategy reported provides a facile way for constructing a wide range of switchable surfaces.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Mechanical
Rita Ferreira, Oscar Carvalho, Luis Sobral, Sandra Carvalho, Filipe Silva
Summary: The radial surface coating layer of compression piston rings is used to improve wear resistance in internal combustion engines. However, the friction coefficient of the piston ring-cylinder liner pair at top dead centers negatively affects the engine's tribological performance. This study tested dimples with different texture dimensions and densities in a home-developed tribometer and found that the texture with an aspect ratio of 0.25 and a density area of 15% yielded the best tribological results.
Review
Engineering, Mechanical
Meng Li, Wenbin Shi, Jun Shi, Tao Wang, Liping Shi, Xiaolei Wang
Summary: This article provides an overview of the recent research progress in modifying the wet friction characteristics of soft elastomers through surface texturing. It discusses the physical mechanisms, methods of regulating wet sliding behaviors, and the prospects and challenges of texture design for soft materials.
Article
Thermodynamics
Wen Yang, Fei Zhou, Xing Chen, Kangqun Li, Junjie Shen
Summary: This paper studies the thermal performance of air-cooled battery thermal management (BTM) for honeycomb-type cylindrical lithium-ion battery pack. It proposes the design of an air distribution plate (ADP) for improving temperature consistency and analyzes the cooling performance and velocity distribution using computational fluid dynamics (CFD). The results show that the ADP battery module reduces the maximum temperature and temperature difference compared to the normal module, and the temperature difference can be maintained within 2 K with improved ADP structure and bionic heat sinks.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Kangqun Li, Fei Zhou, Xing Chen, Wen Yang, Junjie Shen, Zebin Song
Summary: This study proposes an improved adaptive cubature Kalman filter algorithm for estimating the state of charge of lithium-ion batteries. By using an electro-thermal model and QR decomposition, the accuracy of the SOC estimation is enhanced. Experimental results under different working conditions and temperatures validate the stability and accuracy of the algorithm.
Article
Thermodynamics
Xiaobin Xu, Xing Chen, Junjie Shen, Jizhou Kong, Hengyun Zhang, Fei Zhou
Summary: In this study, a biomimetic cephalofoil fin coupled with phase change material was proposed for air-cooling thermal management system of prismatic battery module. The numerical model with experimentally measured heat generation rate and specific heat capacity was used to evaluate performance. The results showed that the use of phase change material and cepha-lofoil fin structure can effectively reduce the maximum temperature of the battery module. Optimization of fin structure parameters can further improve temperature consistency. The use of film heaters can preheat the battery module within a short period of time with good temperature consistency.
APPLIED THERMAL ENGINEERING
(2023)
Article
Physics, Applied
Qingwen Dai, Hao Xu, Chenbo Ma, Wei Huang, Xiaolei Wang
Summary: Inspired by liquid bridge bearings, a ferrofluid (FF) bearing is proposed in this work. The bearing consists of two plates with FF sandwiched between them and a cylindrical magnet implanted in the lower plate to restrain and position the FF. The carrying capacity of the liquid bridge and FF bearing is tested and compared, and the results show that the FF bearing provides a higher maximum force and more stable supporting performance due to the magnetic field effect.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Jianguo Qian, Fei Zhou, Maoda Zhang, Qianzhi Wang, Jizhou Kong
Summary: This study constructed three composite films, CrSiCN, CrBCN, and CrSiBCN, using closed-field unbalanced magnetron sputtering technology as protective films on silicon wafers and 316L stainless steel substrates to protect wearable device shell materials from corrosion caused by human sweat. The electrochemical behavior of Si and B element doped films under acidic and alkaline artificial sweat was investigated, along with the microstructural changes of the films. The results showed that the corrosion rate of the films was higher in acidic artificial sweat due to higher concentrations of chloride ions, hydrogen ions, and lactic acid corrosive ions, while the doping of boron element decreased the corrosion rate in acidic sweat and the dense and smooth surface of CrSiCN film enhanced its corrosion resistance in alkaline sweat.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2023)
Article
Electrochemistry
Yi-Chao Wang, Zhi-Wei Liu, Peng Xu, Zhuo-Qi Hong, Ji-Zhou Kong, Qian-Zhi Wang, Hong-Yu Wei, Fei Zhou
Summary: This study investigates the use of lanthanide elements to modify a layered oxide cathode through solid-state calcination. Based on the findings, the modified cathodes demonstrated enhanced electrochemical performance, as lanthanide modification played dual roles in doping and coating.
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
(2023)
Article
Chemistry, Physical
Da Lei, Qianzhi Wang, Fei Zhou, Jizhou Kong, Zhifeng Zhou
Summary: To continuously update the prediction model based on expanding data set solely, this study established an elastic weight consolidation (EWC)-based artificial neural network (ANN) model, which demonstrated good performance on both new and old data. The R2 coefficient of the EWC-based ANN model remained high even after training with expanding dataset, indicating its practicality and time-saving advantage.
SURFACE REVIEW AND LETTERS
(2023)
Article
Thermodynamics
Chuchen Yue, Qingwen Dai, Wei Huang, Xiaolei Wang
Summary: This study reports on droplets bouncing on curved surfaces with elevated temperatures, confirming the bouncing and depositing phenomena of different lubricant droplets. The influence of initial diameter, tangential velocity, and surface roughness on the impact dynamics of silicone oil droplets on wetted curved surfaces is investigated, with emphasis on the temperature dependence of the bouncing phenomenon. Bouncing and depositing thresholds under various conditions are summarized, with surface roughness having the most significant negative effect on the bounceable velocity range, followed by initial diameter and tangential velocity. A theoretical model and force analysis are established to explain the bouncing mechanism, while modified Bond numbers and Ohnesorge numbers are introduced to predict the bouncing thresholds. This work provides sufficient experimental and theoretical insights into manipulating droplets bouncing on wetted and curved surfaces with elevated temperatures.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Analytical
Yi-Chao Wang, Liang Wen, Zhi-Wei Liu, Peng Xu, Si-Lai Zheng, Ming-Guang Liu, Ji-Zhou Kong, Qian-Zhi Wang, Hong-Yu Wei, Fei Zhou, Kostya Ken Ostrikov
Summary: In order to address safety issues, a robust ethanol-based coating process is used to coat LiNi0.8Co0.1Mn0.1O2 cathode material with polyanionic compound TiP2O7. The coating layer improves the Li+ diffusion capability and electrochemical polarization, and protects the electrode from side reactions and dissolution of transition metal ions.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Materials Science, Coatings & Films
Jianguo Qian, Fei Zhou, Kangqun Li, Qianzhi Wang, Jizhou Kong, Zhifeng Zhou
Summary: Nb-Zr-N composite films were successfully deposited on Si (100) wafers and 316 L substrates through DC magnetron sputtering. Orthogonal experiment and mechanical properties optimization were performed to design the deposition parameters. The microstructure and tribological properties of the films were analyzed, revealing a face-centered cubic solid solution mixed structure for the Nb-Zr-N films with Zr concentration ranging from 3 at.% to 14 at.%. The Nb-Zr-N films exhibited high hardness and elastic modulus, with maximum values of 18.2 GPa and 208 GPa, respectively. The film's high yield strength was attributed to solid solution strengthening and grain refining, while the Zr/Nb atomic ratio affected the average grain size and lattice constant. Nb-Zr-N film deposited at the combination parameter (A1B4C4), which had a Zr/Nb atomic ratio of 0.07, showed excellent tribological properties in air.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Coatings & Films
Jianguo Qian, Fei Zhou, Qianzhi Wang, Jizhou Kong, Zhifeng Zhou
Summary: NbMoSiC gradient films were successfully deposited on 316L stainless steel by adjusting sputtering power of carbon target. The films exhibited a carbon composition gradient and multiphase structures, resulting in improved hardness and corrosion resistance. The enhanced inhibition effect on ion transport during corrosion reaction was also observed. The dense microstructure formed by the carbon composition gradient structure contributed to the improved corrosion resistance of 316L stainless steel.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Coatings & Films
Jianguo Qian, Fei Zhou, Qianzhi Wang, Jizhou Kong, Zhifeng Zhou
Summary: By investigating the microstructure and mechanical properties of NbMoSiC composite films, it is found that the sample C250 with a carbon content of 35.02 at.% exhibits higher hardness, elastic modulus, excellent wear resistance, and superior corrosion resistance. However, increasing the carbon target sputtering power leads to escalated surface roughness and microchannels, ultimately resulting in reduced wear and corrosion performance.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Materials Science, Coatings & Films
Fei Zhou, Jianguo Qian, Maoda Zhang, Yaojia Wu, Qianzhi Wang, Zhifeng Zhou
Summary: CrMoN/Ag coatings were deposited on Ti6Al4V alloys using magnetron sputtering technique, and the mechanical and tribocorrosion properties were investigated. The results showed that the hardness and tribocorrosion performance of the coatings were significantly influenced by the Ag content, with the best performance observed in coatings with an Ag content of 1.87 at.%.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Chemistry, Physical
Binbin Su, Jianhe Ye, Xianghe Zou, Lirong Huang, Xiaolei Wang
Summary: The splitting of the liquid film into isolated micro zones is an important function of the hexagonal texture. The orientation and size of the hexagonal texture have noticeable effects on the drainage rate. Residual micro-droplets are entrapped within the contact regions of single hexagonal micro-pillars and gradually shrink as the hexagonal texture downsizes. A novel geometrical shape is proposed to improve the drainage efficiency.
