Numerical study of pattern formation in compliant surfaces scraped by a rigid tip

Abstract

The emergence of surface patterns on the surfaces of compliant materials subject to plowing wear is a complex problem which can be quantitatively characterized, e.g., on polymer surfaces scraped by an atomic force microscope (AFM) tip. Here we explore the applicability of a phenomenological model recently introduced to describe this phenomenon. Based on the competition between the viscoplastic indentation and the elastic shear stress caused by the tip, the model is able to reproduce the wavy features (ripples) observed when the tip is scanned along a series of parallel lines. For low values of the driving velocity v and the spacing b between scan lines, the existence of dotted areas formed by variously oriented pit alignments is observed. Moreover, coexistence of rippled with dotted domains is also observed at suitable parameter values. The formation process of the ripples is also described in detail. The amplitude, period, and orientation of these features are estimated numerically for different values of v and b parameters. We have also revisited the formation of the wavy patterns formed when a single line is scanned, and derived an equation which correctly describes their period and depth, and the static friction as well. This equation is not applicable when several lines are scanned one after the other and the ripples emerge as result of a cooperative process which involves the scanning of several lines.

Fabrication of nanoindentation array-based SERS substrate using Conical and Berkovich indenters

“…13 Some scholars have used nanoscratching and nanoindentation approaches to fabricate periodic sinusoidal nanostructures and micro/nanopits structures. 7,[14][15][16][17][18][19][20] For the nanoscratching method, a novel machining technique for the sinusoidal structure based on stick-slip mechanism of polymer materials is proposed by several scholars. 14,15 The orientation of the sinusoidal structure is perpendicular to the scratching direction of the probe.…”

“…7,14–20 For the nanoscratching method, a novel machining technique for the sinusoidal structure based on stick-slip mechanism of polymer materials is proposed by several scholars. 14,15 The orientation of the sinusoidal structure is perpendicular to the scratching direction of the probe. In our previous study, 16 nanodots structures could be obtained by the two overlapping scratching processes, which could be used as a SERS substrate to detect the absorption manner of lysozyme on an Ag substrate.…”