Morphological and electrical properties of stretched nanoparticle layers IVANČO Ján 1,a , VÉGSÖ Karol 1,b , ŠIFFALOVIČ Peter 1,c , KOSTIUK Dmytro 1,d , HALAHOVETS Yuriy 1,e , KLAČKOVÁ Ivana 2,f , KOTLAR Mario 3,g , LUBY Štefan 1,h and MAJKOVÁ Eva 1,i 1 Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84511 Bratislava, Slovakia 2 Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, SK-812 19 Bratislava, Slovakia 3 STU Centre for Nanodiagnostics, Vazovova 5, SK-812 43 Bratislava a jan.ivanco@savba.sk, b karol.vegso@savba.sk, c peter.siffalovic@savba.sk, d kostyuk.dmytro@gmail.com, e yurij.halahovec@savba.sk, f xklackova@stuba.sk, g mario.kotlar@stuba.sk, h stefan.luby@savba.sk, i eva.majkova@savba.sk Keywords: Strain sensor; Strain gauge, Deformation sensor; Stretch-resistor; Nanoparticle arrays; Langmuir-Blodgett films; SAXS. Abstract. To examine perspectives of nanoparticle films in the role of active elements in strain sensors, morphological and electrical properties of self-assembled Au nanoparticle monolayer prepared by modified Langmuir-Schaefer technique onto supporting Mylar foil were studied under elongation. Along the probing of electrical response (characterized by the gauge factor of about 60), the small-angle x-ray scattering (SAXS) characterization assessed an average interparticle distance change, which was shown to vary proportionally to the substrate elongation. The approach allowed to unambiguously address the mechanism of the deformation-resistivity transduction. 1. Introduction The sensors of deformation cover a wide range of applications spanning from traditional pressure gauges to tactile sensors [1,2]. Resistive deformation sensors based on nanoparticle (NP) films supported by a flexible substrate display the gauge factor g = (∆R/R 0 )/(∆E/E 0 )−where ∆R and ∆E are electrical resistance and elongation changes upon strain, whereas R 0 and E 0 are their initial values−as high as 200 [3], 300 [4], and even 700 [5]; the values exceed those obtained on deformation sensors based on e.g. conventional continuous metallic layers by two orders of magnitude. The mechanism responsible for the giant GF of NP films has been suggested to be the film resistivity controlled by interparticle tunnel resistance of closely arranged nanoparticles [3]; the exponential dependence of the tunneling current on the interparticle gap makes the overall resistivity highly responsive to fractional changes of the interparticle distances. Yet, the measurements of the interparticle distance on such NP films have been lacked, thus preventing a direct assessment of structural changes of the active NP film upon strain. For example, the disintegration of the NP films via the formation of cracks between NP islands could not be excluded. Here, we report on resistivity of Au NP monolayer on the deformation of the supported Mylar foil accompanied by a direct assessment of the interparticle distance by means of the small-angle x- ray scattering (SAXS) technique. Key Engineering Materials Vol. 644 (2015) pp 31-34 © (2015) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/KEM.644.31 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 147.213.112.239-06/03/15,15:26:58)