Adhesion and Friction Mechanisms of Polymer-on-Polymer Surfaces

Maeda, Nobuo; Chen, Nianhuan; Tirrell, Matthew; Israelachvili, Jacob N.

doi:10.1126/science.1072378

Cited by 294 publications

(248 citation statements)

References 14 publications

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“…The JKR theory has been found to work well for ''ideal'' (clean, smooth, elastic) surfaces with known adhesion energies, e.g., mica coated with surfactant monolayers (22) or smooth layers of elastomeric polymers (10)(11)(12), showing no hysteresis, namely, the loading-unloading paths described by Eq. 1 are reversible, and predicting the correct (thermodynamic) values for ␥ to better than 10%.…”

Section: Resultsmentioning

confidence: 99%

“…The adhesion (detachment) forces and associated surface deformations of glucose-coated mica surfaces were studied using a surface forces apparatus (SFA) (8,(10)(11)(12)37) coupled to interference and optical microscopy imaging.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…However, the adhesion mechanics of viscoelastic materials and sticky fluids are not so well understood (5)(6)(7)(8)(9). The adhesion or fracture energy of viscoelastic, such as some polymer, materials can be four orders of magnitude greater than the thermodynamic value, which has been attributed to such energy-dissipating processes as molecular interdiffusion or entanglements across the contact junction and macroscopic viscous/plastic deformations (10)(11)(12). In addition, detaching viscoelastic materials exhibit various interfacial instabilities and cavitation, which are also not yet understood (13)(14)(15)(16).…”

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confidence: 99%

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Adhesion and detachment mechanisms of sugar surfaces from the solid (glassy) to liquid (viscous) states

Zhao

Zeng

Tian

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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The viscosity of some sugars varies continuously by Ϸ10 orders of magnitude over a temperature range of 50°C. Sugars are therefore ideal model materials for studying the failure mechanism of materials as they change from the solid to the liquid state. We have used a surface forces apparatus coupled to interference and optical microscopy imaging to study the way two sugar surfaces adhere and detach from adhesive contact. The sugar-coated layers on mica displayed significant loading-unloading hysteresis, and the adhesive strength and failure mechanism during a ''loading-unloading cycle'' depended on the loading rate, contact time, and unloading rate. The failure of two glassy sugar surfaces was manifested by the nucleation of many sharp microcracks at the external boundary that rapidly propagate along the original contact interface. At the other extreme, when the material is a liquid, ''failure'' occurs through the nucleation and inward growth of large rounded ripples, characteristic of a Saffman-Taylor fingering instability. In the transition from glassy to viscous failure, sharp crack tips and smooth rounded fingers coexist during the crack propagation. In addition, whereas the detachment geometry of two glassy surfaces was characterized by a peeling-like mechanism along a plane, the fingers associated with the ''snapping'' of a liquid neck extended in all directions. These findings provide insights into the adhesion and failure mechanisms of materials at the micro/nanoscales and are also relevant to the action of interparticle forces between sugar particles, such as those used in inhalation drug delivery.adhesive failure ͉ fingering instability ͉ crack propagation ͉ contact dynamics E veryday experiences tell that solids fracture and liquids flow.However, for many materials there is no clear boundary between the solid and liquid states (1). Also, a material can behave like either a solid or a liquid depending on the time scale of the observation. A typical material that does this is pitch, which, if hit rapidly with a hammer, shatters like a brittle solid, but can flow like a liquid over periods of years (2). Here, we report on a study of the adhesion and detachment mechanisms of a common sugar, glucose, as it transits from the solid (glassy) to the liquid (viscous) state.The classic Hertz and Johnson-Kendall-Roberts (JKR) theories (3, 4) describe the adhesion and contact mechanics of solids. These theories have been found to hold well for molecularly smooth and nonhysteretic surfaces both at macroscopic and microscopic length scales. However, the adhesion mechanics of viscoelastic materials and sticky fluids are not so well understood (5-9). The adhesion or fracture energy of viscoelastic, such as some polymer, materials can be four orders of magnitude greater than the thermodynamic value, which has been attributed to such energy-dissipating processes as molecular interdiffusion or entanglements across the contact junction and macroscopic viscous/plastic deformations (10-12). In addition, detaching viscoelasti...

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Section: Resultsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Adhesion and detachment mechanisms of sugar surfaces from the solid (glassy) to liquid (viscous) states

Zhao

Zeng

Tian

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…In polymer films, including protein, Overney et al described the friction due to stretching the protruded chain segment, which causes sawtooth patterns in lateral profiles [67]. Stretching of the long molecules is a major origin of friction especially for elastomers [32,37], synthetic polymers [68] and various protein films [35,36]. Plowing [69] and dragging protein chains on the surface [70] can also increase the frictional force.…”

Section: Discussionmentioning

confidence: 99%

Direct Observation of Amyloid Nucleation under Nanomechanical Stretching

et al. 2013

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Self-assembly of amyloid nanofiber is associated with functional and pathological processes such as in neurodegenerative diseases. Despite intensive studies, stochastic nature of the process has made it difficult to elucidate molecular mechanisms for the key amyloid nucleation. Here, we investigated the amyloid nucleation of silk-elastinlike peptide (SELP) using time-lapse lateral force microscopy (LFM). By repeated scanning a single line on a SELP-coated mica surface, we observed sudden stepwise height increases, corresponds to nucleation of an amyloid fiber. The lateral force profiles followed either a worm-like chain model or an exponential function, suggesting that the atomic force microscopy (AFM) tip stretches a single or multiple SELP molecules along the scanning direction, serves as the template for further selfassembly perpendicular to the scan direction. Such mechanically induced nucleation of amyloid fibrils allows positional and directional control of amyloid assembly in vitro, which we demonstrate by generating single nanofibers at predetermined nucleation sites.

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“…An adequate amount of friction is required for motion. Wear and friction have been thoroughly investigated over the past few decades [1][2][3][4][5] . A keyword search "Wear Analysis" resulted in 41,000 articles and, of these, more than 21,000 articles ( Figure 1a) appeared in the past 10 years (between 2006 and 2015).…”

Section: Introductionmentioning

confidence: 99%