Linked Life Data

18044936

Source:http://linkedlifedata.com/resource/pubmed/id/18044936

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2008-2-13
pubmed:abstractText
Using a surface forces apparatus, we have investigated the adhesive and lubrication forces of mica surfaces separated by a molecularly thin, subnanometer film of a high-molecular-weight (2.3 MDa) anionic polysaccharide from the algae Porphyridium sp. adsorbed from aqueous solution. The adhesion and friction forces of the confined biopolymer were monitored as a function of time, shearing distance, and driving velocity under a large range of compressive loads (pressures). Although the thickness of the dilute polysaccharide was <1 nm, the friction was low (coefficient of friction = 0.015), and no wear was ever observed even at a pressure of 110 atm over 3 decades of velocity, so long as the shearing distances were less than twice the contact diameter. Atomic force microscopy in solution shows that the biopolymer is able to adsorb to the mica surface but remains mobile and easily dragged upon shearing. The adhesion (adsorption) of this polysaccharide even to negatively charged surfaces, its stable low friction, its robustness (high-load carrying capacity and good wear protection), and the weak (logarithmic) dependence of the friction force on the sliding velocity make this class of polyelectrolytes excellent candidates for use in water-based lubricant fluids and as potential additives to synovial fluid in joints and other biolubricating fluids. The physical reasons for the remarkable tribological properties of the ultrathin polysaccharide monolayer are discussed and appear to be quite different from those of other polyelectrolytes and proteins that act as thick "polymer brush" layers.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0743-7463
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1534-40
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Adhesion and stable low friction provided by a subnanometer-thick monolayer of a natural polysaccharide.
pubmed:affiliation
Department of Chemical Engineering and Department of Physics, University of California-Santa Barbara, CA 93106, USA. delphine.gourdon@mat.ethz.ch
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't