Macrotribological Studies of Poly(L-lysine)-graft-Poly(ethylene glycol) in Aqueous Glycerol Mixtures

  title={Macrotribological Studies of Poly(L-lysine)-graft-Poly(ethylene glycol) in Aqueous Glycerol Mixtures},
  author={Prathima C. Nalam and Jarred N. Clasohm and Alireza Mashaghi and Nicholas D. Spencer},
  journal={Tribology Letters},
We have investigated the tribological properties of surfaces with adsorbed poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) sliding in aqueous glycerol solutions under different lubrication regimes. Glycerol is a polar, biocompatible liquid with a significantly higher viscosity than that of water. Macrotribological performance was investigated by means of pin-on-disk and mini-traction-machine measurements in glycerol-PLL-g-PEG-aqueous buffer mixtures of varying compositions. Adsorption… 

Figures and Tables from this paper

Exploring lubrication regimes at the nanoscale: nanotribological characterization of silica and polymer brushes in viscous solvents.
Nanotribological properties of silica surfaces, with and without adsorbed, brushlike copolymers of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) and poly(L-lysine)-graft-dextran
Design and network characterization of low friction hydrophilic polyether-urethane coatings
Poly(ethylene glycol) (PEG) is a hydrophilic polymer which is widely used for its biocompatibility, non-toxic and physicochemical properties. Although it is known that PEG is prone to thermal
Tunable cohesion and water lubrication of PEG-g-PMHS-c-PMVS copolymer membranes
Abstract This paper reports a new technique that grafts poly (ethylene glycol) (PEG) onto polydimethylsiloxane (PDMS) to enhance the cohesion and water lubrication performances of PDMS. The technique
Aqueous lubricating properties of charged (ABC) and neutral (ABA) triblock copolymer chains
Abstract Application of charged polymer chains as additives for lubricating neutral surfaces in aqueous environment, especially via polymer physisorption, is generally impeded by the electrostatic
Synthesis, Characterization, and Aqueous Lubricating Properties of Amphiphilic Graft Copolymers Comprising 2-Methoxyethyl Acrylate
Amphiphilic anionic and cationic graft copolymers possessing poly(2-hydroxyethyl methacrylate) (PHEMA) backbone and poly(methacrylic acid), poly(2-methoxyethyl acrylate-co-methacrylic acid), and
Adsorption and aqueous lubricating properties of charged and neutral amphiphilic diblock copolymers at a compliant, hydrophobic interface.
The poor adsorption and inferior aqueous lubricating properties of the PAA-based diblock copolymers compared to their PEG-based counterparts are ascribed to the electrostatic repulsion between charged PAA blocks, hindering the facile formation of the lubricating layer under cyclic tribological stress at the sliding PDMS-PDMS interface.
Preparation of poly (N-isopropylacrylamide) brush bonded on silicon substrate and its water-based lubricating property
The poly (N-isopropylacrylamide) brush was covalently bonded on an initiator-coated silicon wafer via surface-initiated atom transfer radical polymerization. The polymer brush was (76.2±0.1) nm in
Aqueous Lubrication with Poly(Ethylene Glycol) Brushes
Hydrophilic polymer brushes constitute a man-made approach to imitating nature’s lubrication mechanisms. A polymer that has been frequently used to explore such systems is poly(ethylene glycol)
Understanding the role of viscous solvent confinement in the tribological behavior of polymer brushes: A bioinspired approach
Polymer brushes consisting of micrometer-long poly(dodecyl methacrylate) (P12MA) chains can impart very low coefficients of friction to surfaces sliding in oil. Under harsh tribological conditions,
Responsive polysaccharide-grafted surfaces for biotribological applications
The elucidation of biolubrication mechanisms and the design of artificial biotribological contacts requires the development of model surfaces that can help to tease out the cues that govern friction


The Influence of Molecular Architecture on the Macroscopic Lubrication Properties of the Brush-Like Co-polyelectrolyte Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) Adsorbed on Oxide Surfaces
The co-polymer poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) has been investigated as a potential biomimetic boundary-lubrication additive for aqueous lubrication systems. In this work, the
Lubrication Properties of a Brushlike Copolymer as a Function of the Amount of Solvent Absorbed within the Brush
The shear forces between poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG)-modified SiO2 tribopairs have been measured with colloidal-probe, lateral force microscopy (LFM) and related to the
Boundary Lubrication of Oxide Surfaces by Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) in Aqueous Media
In this work, we have explored the application of poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) as an additive to improve the lubricating properties of water for metal-oxide-based tribo-systems.
Self-healing behavior of a polyelectrolyte-based lubricant additive for aqueous lubrication of oxide materials
We report on the self-healing behavior of a polyelectrolyte-based aqueous lubricant additive, poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG), during aqueous lubrication of an oxide-based
Aqueous Lubrication of SiC and Si3N4 Ceramics Aided by a Brush-like Copolymer Additive, Poly(l-lysine)-graft-poly(ethylene glycol)
We have examined the adsorption properties of poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG)—a brush-like polymer—on Si3N4 and SiC surfaces and determined its impact on the aqueous
Nanotribology of surface-grafted PEG layers in an aqueous environment.
  • T. Drobek, N. Spencer
  • Materials Science, Medicine
    Langmuir : the ACS journal of surfaces and colloids
  • 2008
The lubrication properties of adsorbed poly(L-lysine)-graft-poly(ethylene glycol) in aqueous buffer solution were studied with the surface forces apparatus. In general, the polymer brushes revealed
Preferential Solvation and Its Effect on the Lubrication Properties of a Surface-Bound, Brushlike Copolymer
We have investigated the collapse−stretching transition of a surface-bound, brushlike copolymer, poly(l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG), and the consequence of such transitions on the
Relationship between interfacial forces measured by colloid-probe atomic force microscopy and protein resistance of poly(ethylene glycol)-grafted poly(L-lysine) adlayers on niobia surfaces.
The data demonstrate the importance of an ionic-strength-dependent minimum PEG layer thickness to screen the electrostatic interactions of charged interfaces and to advance interpretation of protein adsorption or repellence beyond the oversimplified steric barrier model.
Reduction of friction at oxide interfaces upon polymer adsorption from aqueous solutions.
Measurements of interfacial friction as a function of applied load reveal a significant reduction in friction upon the adsorption of the polymer, as well as sensitivity to the coated nature of the interface (single-sided versus two-sided) and the composition of the Adsorbed polymer.
Interaction forces and morphology of a protein-resistant poly(ethylene glycol) layer.
A molecular model for the adsorbed copolymer morphology is proposed, suggesting the existence of a weak equilibrium network between poly(ethylene glycol) and water--a finding in accordance with the remarkable solution properties of PEG.