Fabrication of Strain Gauges via Contact Printing: A Simple Route to Healthcare Sensors Based on Cross-Linked Gold Nanoparticles.
In this study, we developed a novel and efficient process for the fabrication of resistive strain gauges for healthcare-related applications. First, 1,9-nonanedithiol cross-linked gold nanoparticle (GNP) films were prepared via layer-by-layer (LbL) spin-coating and subsequently transferred onto flexible polyimide foil by contact printing. Four-point bending tests revealed linear response characteristics with gauge factors of ∼14 for 4 nm GNPs and ∼26 for 7 nm GNPs. This dependency of strain sensitivity is attributed to the perturbation of charge carrier tunneling between neighboring GNPs, which becomes more efficient with increasing particle size. Fatigue tests revealed that the strain-resistance performance remained nearly the same after 10.000 strain/relaxation cycles. We demonstrate that these sensors are well suited to monitor muscle movements. Furthermore, we fabricated all-printed strain sensors by directly transferring cross-linked GNP films onto soft PDMS sheets equipped with interdigitated electrodes. Due to the low elastic modulus of poly(dimethylsiloxane) (PDMS), these sensors are easily deformed and, therefore, they respond sensitively to faint forces. When taped onto the skin above the radial artery, they enable the well-resolved and robust recording of pulse waves with diagnostically relevant details.
['Ketelsen|Bendix|B|http://orcid.org/0000-0002-8895-9835', 'Yesilmen|Mazlum|M|', 'Schlicke|Hendrik|H|http://orcid.org/0000-0002-6977-4042', 'Noei|Heshmat|H|http://orcid.org/0000-0003-1294-3527', 'Su|Chun-Hao|CH|', 'Liao|Ying-Chih|YC|http://orcid.org/0000-0001-9496-4190', 'Vossmeyer|Tobias|T|http://orcid.org/0000-0001-9738-3826']
D015374:Biosensing Techniques D003432:Cross-Linking Reagents D004129:Dimethylpolysiloxanes D004566:Electrodes D004867:Equipment Design D006046:Gold D006801:Humans D008422:Materials Testing D053768:Metal Nanoparticles D046529:Microscopy, Electron, Transmission D018482:Muscle, Skeletal D010316:Particle Size D011327:Printing
strain gauge printing sensor gold nanoparticle polyimide PDMS pulse