Friction at nanopillared polymer surfaces beyond Amontons' laws: Stick-slip amplitude coefficient (SSAC) and multiparametric nanotribological properties

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:583

Article

Ishak, Mohd I.^1,2,3  Dobryden, Illia^4,5  Claesson, Per Martin⁴  Briscoe, Wuge H.²  Su, Bo¹ 

[1] Univ Bristol, Bristol Dent Sch, Lower Maudlin St, Bristol BS1 2LY, Avon, England

[2] Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England

[3] Univ Malaysia Perlis, Fac Engn Technol, Perlis, Malaysia

[4] KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Drottning Kristinas Vag 51, SE-10044 Stockholm, Sweden

[5] Lulea Univ Technol, Sch Engn Sci & Math, Lulea, Sweden

关键词: Contact mechanics;    Friction;    Stick-slip amplitude coefficient (SSAC);    Amontons' laws of friction;    Nanostructured surfaces;    PET;    Nanotribology;   

DOI  :  10.1016/j.jcis.2020.09.038

来源: Elsevier

【 摘 要 】

Frictional and nanomechanical properties of nanostructured polymer surfaces are important to their technological and biomedical applications. In this work, poly(ethylene terephthalate) (PET) surfaces with a periodic distribution of well-defined nanopillars were fabricated through an anodization/embossing process. The apparent surface energy of the nanopillared surfaces was evaluated using the Fowkes acid-base approach, and the surface morphology was characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The normal and lateral forces between a silica microparticle and these surfaces were quantified using colloidal probe atomic force microscopy (CP-AFM). The friction-load relationship followed Amonton's first law, and the friction coefficient appeared to scale linearly with the nanopillar height. Furthermore, all the nanopillared surfaces showed pronounced frictional instabilities compared to the smooth sliding friction loop on the flat control. Performing the stick-slip amplitude coefficient (SSAC) analysis, we found a correlation between the frictional instabilities and the nanopillars density, pull-off force and work of adhesion. We have summarised the dependence of the nanotribological properties on such nanopillared surfaces on five relevant parameters, i.e. pull-off force f(p), Amontons' friction coefficient mu, RMS roughness R-q, stick-slip amplitude friction coefficient SSAC, and work of adhesion between the substrate and water W-adh in a radar chart. Whilst demonstrating the complexity of the frictional behaviour of nanopillared polymer surfaces, our results show that analyses of multiparametric nanotribological properties of nanostructured surfaces should go beyond classic Amontons' laws, with the SSAC more representative of the frictional properties compared to the friction coefficient. (C) 2020 Elsevier Inc. All rights reserved.

【 授权许可】

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