Article
Chemistry, Physical
Lukas Poggemann, Richard Thelen, Joerg Meyer, Achim Dittler
Summary: The adhesion between particles and a filter fiber plays a crucial role in filtration, affecting the process of separation and detachment of particles during filter regeneration. Experimental measurements using AFM showed a reduced adhesion force between particles and the filter fiber within a certain range of substrate roughness and peak-to-peak distance. The influence of high and low energy surface particulate material was further evaluated.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Multidisciplinary Sciences
I. I. Argatov
Summary: This study presents a first-order asymptotic analysis of the Griffith energy balance in the Johnson-Kendall-Roberts model of adhesive contact under non-symmetric perturbation of the contact geometry. The explicit evaluation of pull-off force and the consideration of the sphere Poisson's ratio in controlling the adhesive pull-off force in a particular case of adhesive contact between a relatively stiff sphere and an elastic half-space are discussed. This article is part of a discussion meeting issue on inventing new tough materials using a cracking approach, where fracture is explored as a stranger phenomenon than friction.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Mechanics
Xiaofei Zhang, Changhong Linghu, Hongyu Luo, Jizhou Song
Summary: Transfer printing is an emerging technique that involves active elastomeric adhesive for non-contact pick-up and printing, showing great potential in the development of stretchable electronics and micro-LED displays.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Engineering, Mechanical
Anle WANG, Martin H. MUESER
Summary: A recent study investigated the adhesion between an elastic body and a smooth, rigid substrate, and found that the surface roughness suppresses adhesion. Simulations revealed that the pull-off force is influenced by different contact patches, resulting in up to four different regimes of adhesion. The study highlights the importance of considering both local and global parameters in understanding adhesion between materials.
Article
Materials Science, Multidisciplinary
G. Violano, A. Chateauminois, L. Afferrante
Summary: The numerical model proposed in this paper describes the adhesive normal contact between a glass spherical indenter and a viscoelastic model rough substrate of PDMS material, taking into account dissipative processes and localized viscoelastic losses at contact lines. The model successfully explains the strong adhesion hysteresis observed in experimental measurements, which is mainly attributed to viscous dissipation occurring during pull-off. The detachment force is found to be influenced by the detachment rate and roughness amplitude, rather than by the maximum load from which unloading starts.
MECHANICS OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Tobias Materzok, Annabelle Canestraight, Stanislav N. Gorb, Florian Muller-Plathe
Summary: In this study, a model of gecko keratin was developed to investigate the influence of electrostatic and van der Waals forces on gecko adhesion. The results showed that the pull-off force increased with increased water content and was inversely related to the water contact angle of the surface. The number and charge density of keratin and water at the surface were also found to play an important role in adhesion.
Article
Engineering, Mechanical
Jiahui Zhao, Keju Ji, Chongwen Tu, Kai Deng, Liuwei Wang, Jian Chen, Jianming Wu, Junjie Zhu, Hemin Bai, Zhendong Dai
Summary: This study designs a biomimetic pad inspired by the external and internal cuticles of insects, and through mechanical analysis, it identifies the optimized structure of the pad that exhibits high frictional attachment.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Mechanics
Weike Yuan, Gangfeng Wang
Summary: This paper presents a simple theoretical model for adhesive contact between a rigid sphere and a circular membrane under constant tension. Analytical relationships between net external force, contact radius, and contact displacement are obtained, with critical contact responses at pull-off force and zero external force presented as functions of a dimensionless adhesion range parameter. The general solution quantifies the transition from the DMT-type limit to the JKR-type limit, potentially advancing adhesion mechanics of thin membranes.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Chemistry, Physical
Rafael de la Madrid, Huy Luong, Jacob Zumwalt
Summary: This study calculates the normal capillary retention force that anchors a drop to a solid surface in the direction perpendicular to the surface and investigates its relationship with the Young-Dupre work of adhesion. Additionally, the study calculates the work required to create or destroy a patch of solid-liquid interface by moving the triple line on a solid substrate. The findings suggest that when the capillary number is small and a drop slides on a surface at a constant speed, the lateral retention force is the primary source of energy dissipation, while viscous dissipation has a minor role to play.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Materials Science, Multidisciplinary
Bo Peng, Qunyang Li, Xi-Qiao Feng, Huajian Gao
Summary: The study highlights the varying impact of interfacial shear stress on adhesion under different contact conditions, with the most significant effect seen when the model approaches the JKR limit and diminishing in the transitional regime to become negligible in the DMT limit. This behavior contrasts with Johnson's phenomenological solution and underscores the importance of considering the reversible interface slip parameter in adhesive contact mechanics.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Materials Science, Multidisciplinary
Taulant Sinani, Dmytro Solonenko, Goran Miskovic
Summary: Advanced packaging solutions require insulation and passivation materials with exceptional properties that can meet the reliability needs of electronics devices. The bonding properties of AF4 parylene coatings, an important packaging coating material, were assessed in this study. Pull-off tests of AF4 coatings on silicon and glass substrates showed significant differences in bonding behavior. Further mechanical and structural characterization revealed differences in modulus and crystallinity between the AF4-Si and AF4-SiO2 samples. Understanding the adhesive properties of AF4 coatings on different substrates advances the usage of AF4 in electronics packaging technologies.
Article
Mechanics
Heather P. H. Liddell, Laura M. Erickson, James P. Tagert, Attilio Arcari, Gregory M. Smith, James Martin
Summary: This paper examines the pull-off adhesion test from a fracture mechanics perspective and presents two microscopy-based methods for extracting analytically useful fracture data. One method obtains mode mixity from observed crack kink angles, while the other method uses machine learning-based image segmentation to quantify the fractional area coverage of materials removed with the pull stub. These techniques have both immediate utility for data enhancement in pull-off adhesion tests and long-term potential as tools for failure analysis in coated systems.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Materials Science, Characterization & Testing
Ilya A. Morozov
Summary: Polyurethane elastomer was studied by atomic force microscopy under fast nanoindentation conditions to investigate surface characteristics. The research found that the hard phase is unevenly distributed with the soft phase, and the indentation rate is influenced by various factors.
Article
Mechanics
Raymond H. Plaut
Summary: The study examines the use of pressure to adjust the strength of adhesion by analyzing the upward pull-off of punches of different shapes from plates of corresponding shapes, considering both force control and displacement control. The effects of pressure increase on pull-off force and punch displacement are investigated using von Karman theory.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2021)
Article
Engineering, Chemical
Yunong Zhou
Summary: In this study, the effects of thermal fluctuations on the generalized JKR model were investigated. The distribution of pull-off forces was found to be similar to the Bradley model, with an increase in temperature leading to a broadening of the distribution and a reduction of the pull-off force. The pull-off force, separated into athermal and thermal-induced reduction terms, was shown to be significantly enhanced with increasing velocity for compliant springs.
Article
Engineering, Chemical
Jaylene Martinez, Masoud Aghajani, Yinan Lu, Adrienne K. Blevins, Shouhong Fan, Mengyuan Wang, Jason P. Killgore, Stefano Berti Perez, Jaivin Patel, Christina Carbrello, Sean Foley, Ryan Sylvia, Rong Long, Robert Castro, Yifu Ding
Summary: This study investigated the kinetics of capillary infiltration of viscous polypropylene in polyethersulfone membranes with different hydrophilicities, finding that infiltration dynamics are influenced by various factors. The mechanical integrity of the bonded films decreases slightly with increasing infiltration depth, as quantified by a modified T-peel test.
JOURNAL OF MEMBRANE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Chung-Yuen Hui, Bangguo Zhu, Rong Long
Summary: We compare different theories on the steady state growth of a Mode I crack in linear viscoelastic solids and test these theories against experimental data. Realistic constitutive models are used in the analytical solutions, and new results such as the strain field near the crack tip and the investigation of the viscoelastic trumpet shape and size are presented.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Chemistry, Physical
Zezhou Liu, Hao Dong, Anand Jagota, Chung-Yuen Hui
Summary: This study proposes a numerical scheme for solving lubrication problems that does not require iteration, and is stable, efficient, and automatic. Experimental results are in excellent agreement with the numerical solution.
Article
Engineering, Mechanical
Mahyar Afshar-Mohajer, Xingwei Yang, Rong Long, Min Zou
Summary: This study investigates the friction and deformation behavior of micro/nano-hierarchical textures, revealing a coupling between micropillar deformation and nanohair height. Furthermore, it is found that the bending of long nanohairs can provide assistive sliding forces, and lateral force can develop even before sliding due to the buckling of longer nanohairs.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Chemical
Haibin Wu, Anand Jagota, Chung-Yuen Hui
Summary: In this study, we investigate the lubricated sliding of a rigid cylinder on a viscoelastic half space with a single characteristic retardation time using a numerical scheme. Our results show that the total friction force can be decomposed into viscoelastic and hydrodynamic components. We find that the viscoelastic component can be well approximated by the dry limit, while the hydrodynamic component can be approximated by a modification of the elastic limit. We also examine the effects of parameters on the hydrodynamic pressure, film thickness, and friction coefficient.
Article
Engineering, Chemical
Nichole Moyle, Hao Dong, Haibin Wu, Constantine Y. Khripin, Chung-Yuen Hui, Anand Jagota
Summary: Controlling the lubricated sliding friction of compliant contacts is crucial in mechanical and biological systems. In this study, a structured two-phase material composed of a plastic mesh embedded in a compliant elastomer matrix was developed. The results showed that the embedded mesh structure exhibited increased lubricated sliding friction under specific conditions. Simulations suggested that the difference in lubrication regimes between the structured sample and the unstructured control was caused by areas of high contact pressure induced by the increased local contact stiffness near the embedded mesh.
Article
Polymer Science
Jingwen Zhao, Jingyi Guo, Costantino Creton, Chung Yuen Hui, Tetsuharu Narita
Summary: Mechanical reinforcement of hydrogels is crucial in gel science. Dual cross-linked hydrogels with both chemical and transient cross-links exhibit enhanced mechanical properties compared to chemically cross-linked gels alone. This study investigates the effect of the ratio of chemical and transient cross-links on chain dynamics using model dual poly(vinyl alcohol) cross-linked gels. The results suggest that the characteristic time of network relaxation increases with decreasing concentration of transient cross-linkers, and the characteristic time distribution gradually transitions from Maxwell-like to Rouse-like relaxation.
Article
Materials Science, Multidisciplinary
XiaoHao Sun, Ke Wang, HengAn Wu, Jian Chen, Rong Long
Summary: The finite element method is widely used to simulate the process of cells entering narrow channels. This study focuses on the effects of frictional boundary conditions in these simulations. By continuously updating the boundary conditions according to the contact status, the researchers study how pressure boundary conditions and friction coefficient affect the simulated cell entry process. The results show that different pressure boundary conditions produce the same result under frictionless contact but considerably different results under frictional contact. Furthermore, a larger friction coefficient can significantly reduce the entry length under a prescribed pressure or a certain entry time.
MECHANICS OF MATERIALS
(2022)
Article
Engineering, Chemical
Brodie K. Hoyer, Rong Long, Mark E. Rentschler
Summary: Rolling contact experimentation is a useful method for studying adhesive contact between surfaces. The researchers have designed a tribometric device to capture forces between a rolling indenter and substrate, and validated its effectiveness through experiments. This device can facilitate investigations of rolling contact mechanics in medical robotics.
Article
Engineering, Mechanical
Karl Johannes, Kristin Calahan, Leah Bowen, Emily Zuetell, Rong Long, Mark Rentschler
Summary: This study investigates the adhesion modulation of an elastomeric micro-patterned surface with both rigid and soft materials by applying equibiaxial tensile strain. Experimental results show that the applied strain substantially influences the adhesion behavior of the surface with both types of probes, with a different underlying mechanism for each.
EXTREME MECHANICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Chung-Yuen Hui, Bangguo Zhu, Matteo Ciccotti
Summary: This article investigates stress concentration in sharp corners or wedge structures and explores the changes caused by considering large deformation. The study found that, under large deformation, the stress field differs from the predictions of linear elasticity and does not exhibit oscillations.
INTERNATIONAL JOURNAL OF FRACTURE
(2022)
Article
Physics, Multidisciplinary
Xuechen Shi, Zezhou Liu, Luyi Feng, Tiankai Zhao, Chung-Yuen Hui, Sulin Zhang
Summary: The study investigates the elastocapillary effect at cell-matrix contacts and its impact on tissue morphogenesis, wound healing, and cancer metastasis. By observing cell colonies indenting soft hydrogels, the researchers propose a two-step traction force microscopy to separate active cell traction from interfacial stresses. The study provides a foundation for understanding elastocapillarity-induced mechanobiological processes in cells and tissues.
Article
Materials Science, Multidisciplinary
Haibin Wu, Chung -Yuen Hui, Anand Jagota
Summary: This paper investigates the problems in elasto-hydrodynamic lubrication when one of the contacting bodies is elastically soft. A numerical method is developed to solve both normal indentation and transient sliding lubrication problems, avoiding the difficulties of converging iterative methods.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Mechanical
Jikun Wang, Kunpeng Cui, Bangguo Zhu, Jian Ping Gong, Chung-Yuen Hui, Alan T. Zehnder
Summary: Relaxation experiments were conducted on single edge notch tension (SENT) and T shape specimens made of various polyampholyte (PA) hydrogels. These specimens have the common feature of containing regions with high and low stress/strain, allowing us to investigate the load transfer mechanisms between permanent and dynamic networks of different strengths, which are related to viscoelastic behavior. PA gels exhibit non-linear viscoelasticity, with time-dependent behavior controlled by the breaking and reforming of ionic bonds in the dynamic network. Contrary to the prediction of linear viscoelastic theory, the displacement and strain fields during stress relaxation change in a complex manner depending on the strength of the dynamic bonds and the observation time window. These experimental findings are explained by a non-linear viscoelastic model. Additional physical insights are obtained by studying the non-linear rheology of dynamic bonds or stickers. Our results demonstrate that modifying the strength of dynamic bonds can control the load transfer between networks.
EXTREME MECHANICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Hao Dong, Nichole Moyle, Haibin Wu, Constantine Yuri Khripin, Chung-Yuen Hui, Anand Jagota
Summary: Lubricated contacts in soft materials are common in various applications. The transition between elasto-hydrodynamic lubrication (EHL) and mixed lubrication (ML) regimes governs the minimum sliding friction achievable. Previous belief held that the transition occurs when the thickness of the lubricant layer is comparable with the amplitude of surface roughness, but this study found that the transition can occur when the thickness of the liquid layer is much larger than the height of the asperities. Direct visualization showed the formation of wave-like surface wrinkles triggering the transition to the mixed regime.
ADVANCED MATERIALS
(2023)
