The role of human skin condition on active touch of wood and polymers

T

he role of human skin condition on

active touch of wood and polymers

prof. Emile van der Heide Adriana Rodríguez

Urribarrí MSc.

Wood surfaces

Polymer surfaces

A. C. Rodríguez Urribarrí

_{, X. Zeng}

_{, G.R.B.E. Römer}

_{and E. van der}

Heide

1 _{Laboratory of Surface technology and Tribology, University of Twente, NL 2Applied Laser Technology,}

Faculty of Engineering Technology, University of Twente, NL 3 _{TNO, NL}

*contact: a.c.rodriguezurribarri@utwente.nl

Introduction

Friction, surface finish and moisture between the human skin and a surface are critical factors influencing the sensation of comfort or discomfort generated during active touch. The sensation of comfort is in many cases associated to the feel of organic materials such as wood. Therefore, there is an increased interest to develop polymeric materials with similar touch properties.

Figure 1. Tactile experience during touch [1].

Objective

This study was conducted to analyse the friction response during tactile touch of wood and polymers, such as the static and dynamic friction coefficients, as a function of the skin condition.

Method

• In vivo friction measurements were carried out on ‘as received’ and surface modified samples of hardwood and softwood.

• Polymer samples with random like and deterministic (laser textured - grooves) surface patterns were selected for further comparison.

Figure 2. In vivo friction measurements.

Static vs dynamic friction coefficients

as a function of the skin condition

Natural wood vs polymer random like

and deterministic surfaces

Results

• µ_Static and µ_dynamic from wood samples ranged from 0.25 to 0.45 and 0.2 to 0.4 respectively under dry condition.

• Polyethylene and Polypropylene samples showed dynamic friction coefficients of similar values to that of the wood samples. • Polyamide 12 and Polyamide 66 exhibited

static friction coefficients of similar range of values to that obtained with the wood samples.

Conclusions

• µ_Static obtained for selected wood samples in dry and wet condition were not always higher than µ_dynamic.

• Friction coefficients of wood samples were found in agreement with two kinds of polymer samples. dr. Gert-Willem Römer 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.00 0.50 1.00 1.50 2.00 µ [ -] Time [s] STD µ_Static µ_Dynamic Deterministic polymer surfaces 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70

Static Dynamic Static Dynamic

Dry skin Wet skin

µ [ -] Skin condition Wood Polymers

Acknowledgements

European Fund for Regional Development: GO EFRO 209-18331.

References

[1] 2007. Life: The science of biology, 8th _Edition: