Surface forces apparatus
View article
New tricks for old dogs: improving the accuracy of biomolecular force fields by pair-specific corrections to non-bonded interactions Open
Recent advances in parallel computing have pushed all-atom molecular dynamics simulations into an untested territory. This article reviews the applications of the NBFIX approach for testing and improving molecular dynamics force fields and…
View article
Adhesion and surface forces in polymer tribology—A review Open
Polymer tribology is a fast growing area owing to increasing applications of polymers and polymer composites in industry, transportation, and many other areas of economy. Surface forces are very important for polymer contact, but the real …
View article
Origins of Extreme Liquid Repellency on Structured, Flat, and Lubricated Hydrophobic Surfaces Open
There are currently three main classes of liquid-repellent surfaces: micro- or nanostructured superhydrophobic surfaces, flat surfaces grafted with "liquidlike" polymer brushes, and lubricated surfaces. Despite recent progress, the mechani…
View article
The role of intermolecular forces in contact electrification on polymer surfaces and triboelectric nanogenerators Open
The present study reports the origin of surface charge on the polymer surface upon triboelectrification and is a step forward towards the development of next generation of mechanical energy harvesting systems.
View article
The Role of Hyaluronic Acid in Cartilage Boundary Lubrication Open
Hydration lubrication has emerged as a new paradigm for lubrication in aqueous and biological media, accounting especially for the extremely low friction (friction coefficients down to 0.001) of articular cartilage lubrication in joints. A…
View article
Direct Measurement of the Surface Energy of Graphene Open
Graphene produced by chemical vapor deposition (CVD) is a promising candidate for implementing graphene in a range of technologies. In most device configurations, one side of the graphene is supported by a solid substrate, wheras the other…
View article
Surface strain measurements of fingertip skin under shearing Open
The temporal evolution of surface strain, resulting from a combination of normal and tangential loading forces on the fingerpad, was calculated from high-resolution images. A customized robotic device loaded the fingertip with varying norm…
View article
Surface force measurements and simulations of mussel-derived peptide adhesives on wet organic surfaces Open
Significance The need for bio-inspired wet adhesives has significantly increased in the past few decades (e.g., for dental and medical transplants, coronary artery coatings, cell encapsulants, etc.). However, the molecular basis behind cat…
View article
Wear Protection without Surface Modification Using a Synergistic Mixture of Molecular Brushes and Linear Polymers Open
We describe the design of lubricating and wear protecting fluids based on mixtures of bottle-brushes (BB) and linear polymer solutions. To illustrate this concept, we used hyaluronic acid (HA), a naturally occurring linear polyelectrolyte,…
View article
Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment Open
Significance Crystal growth through nanoparticle assembly appears to be a common phenomenon in synthetic, biological, and geochemical settings, and can lead to formation of hierarchical structures with unique properties tied to this noncla…
View article
Intermolecular Interactions between Bottlebrush Polymers Boost the Protection of Surfaces against Frictional Wear Open
Polymers exhibiting the bottlebrush (BB) architecture have excellent lubricating properties. However, to motivate their use in real life systems, they must also protect surfaces against frictional damage. In this article, we synthesized a …
View article
Surface Forces Apparatus Measurements of Interactions between Rough and Reactive Calcite Surfaces Open
nm-Range forces acting between calcite surfaces in water affect macroscopic properties of carbonate rocks and calcite-based granular materials and are significantly influenced by calcite surface recrystallization. We suggest that the repul…
View article
Molecular behaviors in thin film lubrication—Part one: Film formation for different polarities of molecules Open
There are three unsolved problems in thin film lubrication (TFL) since it was proposed 20 years ago, i.e., the determination of the type of molecules that can enter the contact region efficiently during sliding, the orientation of molecule…
View article
How Slippery are SLIPS? Measuring Effective Slip on Lubricated Surfaces with Colloidal Probe Atmoc Force Microscopy Open
Lubricant-infused surfaces have attracted great attention recently and are described as slippery liquid-infused porous surfaces (SLIPS). Here, we measured the hydrodynamic drainage forces on SLIPS by colloid probe atomic force microscopy (…
View article
Nanolubrication in deep eutectic solvents Open
We report surface force balance measurements of the normal surface force and friction between two mica surfaces separated by a nanofilm of the deep eutectic solvent ethaline.
View article
Intermolecular and surface forces in atomic-scale manufacturing Open
Atomic and close-to-atomic scale manufacturing (ACSM) aims to provide techniques for manufacturing in various fields, such as circuit manufacturing, high energy physics equipment, and medical devices and materials. The realization of atomi…
View article
Structure and Dynamics of Confined Liquids: Challenges and Perspectives for the X-ray Surface Forces Apparatus Open
The molecular-scale structure and dynamics of confined liquids has increasingly gained relevance for applications in nanotechnology. Thus, a detailed knowledge of the structure of confined liquids on molecular length scales is of great int…
View article
Solidification and superlubricity with molecular alkane films Open
Significance An essential step in society’s attempt to reduce energy consumption is to understand and optimize energy dissipation (friction) in mechanical processes. Despite decades of study, one of the most fundamental model systems in th…
View article
Designer Nanoparticles as Robust Superlubrication Vectors Open
Phosphatidylcholine lipid bilayers or liposomes at interfaces in aqueous environments can provide extremely efficient lubrication. This is attributed to the hydration lubrication mechanism acting at the highly hydrated phosphocholine-headg…
View article
Anisotropic Polymer Adsorption on Molybdenite Basal and Edge Surfaces and Interaction Mechanism With Air Bubbles Open
The anisotropic surface characteristics and interaction mechanisms of molybdenite (MoS2) basal and edge planes have attracted much research interest in many interfacial processes such as froth flotation. In this work, the adsorption of a p…
View article
Structure and Functionality of Polyelectrolyte Brushes: A Surface Force Perspective Open
The unique functionality of polyelectrolyte brushes depends on several types of specific interactions, including solvent structure effects, hydrophobic forces, electrostatic interactions, and specific ion interactions. Subtle variations in…
View article
Single‐Molecule Force Spectroscopy Reveals Multiple Binding Modes between DOPA and Different Rutile Surfaces Open
Inspired by marine mussel adhesive systems, numerous 3,4‐dihydroxyphenylalanine (DOPA)‐containing surface coating materials have been recently designed. It is well known that DOPA has a strong adhesion ability to different kinds of wet sur…
View article
Molecular Dynamics Simulations of Glycerol Monooleate Confined between Mica Surfaces Open
The structure and frictional properties of glycerol monooleate (GMO) in organic solvents, with and without water impurity, confined and sheared between two mica surfaces are examined using molecular dynamics simulations. The structure of t…
View article
Solution Structure and Hydration Forces between Mica and Hydrophilic Versus Hydrophobic Surfaces Open
Solid–liquid interfaces are central to a range of interesting phenomena including colloidal aggregation, crystallization by particle attachment, catalysis, heterogeneous nucleation, water desalination, and biomolecular assembly. While thre…
View article
Functionalized graphene-oxide nanosheets with amino groups facilitate macroscale superlubricity Open
Graphene-oxide (GO) has been recognized as an excellent lubrication material owing to its two-dimensional structure and weak interlayer interactions. However, the functional groups of GO that can contribute to anti-friction, anti-wear, and…
View article
Is the boundary layer of an ionic liquid equally lubricating at higher temperature? Open
Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C…
View article
Unraveling capillary interaction and viscoelastic response in atomic force microscopy of hydrated collagen fibrils Open
The mechanical properties of collagen fibrils depend on the amount and the distribution of water molecules within the fibrils. Here, we use atomic force microscopy (AFM) to study the effect of hydration on the viscoelastic properties of re…
View article
Anisotropic Friction in a Ligand-Protein Complex Open
The effect of an externally applied directional force on molecular friction is so far poorly understood. Here, we study the force-driven dissociation of the ligand-protein complex biotin-streptavidin and identify anisotropic friction as a …
View article
Direct Measurement of Interaction Forces between Surfaces in Liquids Using Atomic Force Microscopy Open
The stability of particle suspensions, which is important in numerous industrial processes, is generally dominated by the interaction forces between the suspended particles. Understanding the interaction forces between surfaces in liquids …
View article
Large Effective Slip on Lubricated Surfaces Measured with Colloidal Probe AFM Open
In this work, we study the interfacial boundary conditions at the interface between two immiscible liquids under a laminar flow. We measure the hydrodynamic drainage forces acting on a colloid probe as it approaches a flat and smooth Teflo…