TY - JOUR A1 - Stoyanov, Hristiyan A1 - Mc Carthy, Denis N. A1 - Kollosche, Matthias A1 - Kofod, Guggi T1 - Dielectric properties and electric breakdown strength of a subpercolative composite of carbon black in thermoplastic copolymer N2 - We investigate the dielectric properties and electric breakdown strength of subpercolative composites of conductive carbon black particles in a rubber insulating matrix. A significant increase in the permittivity in the vicinity of the insulator to conductor transition was observed, with relatively low increases in dielectric loss; however, a rapid decrease in electric breakdown strength was inevitable. A steplike feature was ascribed to agglomeration effects. The low ultimate values of the electric field strength of such composites appear to prohibit practical use. Y1 - 2009 UR - http://apl.aip.org/ U6 - https://doi.org/10.1063/1.3154553 SN - 0003-6951 ER - TY - JOUR A1 - Stoyanov, Hristiyan A1 - Kollosche, Matthias A1 - McCarthy, Denis N. A1 - Kofod, Guggi T1 - Molecular composites with enhanced energy density for electroactive polymers N2 - Actuators based on soft dielectric elastomers deform due to electric field induced Maxwell's stress, interacting with the mechanical properties of the material. The relatively high operating voltages of such actuators can be reduced by increasing the permittivity of the active material, while maintaining the mechanical properties and high electrical breakdown strength. Approaches relying on the use of highly polarizable molecules or conjugated polymers have so far provided the best results, however it has been difficult to maintain high breakdown strengths. In this work, a new approach for increasing the electrostatic energy density of a soft polymer based on molecular composites is presented, relying on chemically grafting soft gel-state pi-conjugated conducting macromolecules (polyaniline (PANI)) to a flexible elastomer backbone SEBS-g-MA (poly-styrene-co-ethylene-co-butylene-co-styrene-g-maleic anhydride). The approach was found to result in composites of increased permittivity (470% over the elastomer matrix) with hardly any reduction in breakdown strength (from 140 to 120 V mu m(-1)), resulting in a large increase in stored electrostatic energy. This led to an improvement in the measured electromechanical response as well as in the maximum actuation strain. A transition was observed when amounts of PANI exceeded 2 vol%, which was ascribed to the exhaustion of the MA- functionality of the SEBS-g-MA. The transition led to drastic increases in permittivity and conductivity, and a sharp drop in electrical breakdown strength. Although the transition caused further improvement of the electromechanical response, the reduction in electrical breakdown strength caused a limitation of the maximum achievable actuation strain. Y1 - 2010 UR - http://www.rsc.org/Publishing/Journals/jm/index.asp U6 - https://doi.org/10.1039/C0jm00519c SN - 0959-9428 ER - TY - JOUR A1 - Kollosche, Matthias A1 - Döring, Sebastian A1 - Stumpe, Joachim A1 - Kofod, Guggi T1 - Voltage-controlled compression for period tuning of optical surface relief gratings JF - OPTICS LETTERS N2 - This Letter reports on new methods and a consistent model for voltage tunable optical transmission gratings. Elastomeric gratings were molded from holographically written surface relief gratings in an azobenzene sol-gel material. These were placed on top of a transparent electroactive elastomeric substrate. Two different electro-active substrate elastomers were employed, with a large range of prestretches. A novel finite-deformation theory was found to match the device response excellently, without fitting parameters. The results clearly show that the grating underwent pure-shear deformation, and more surprisingly, that the mechanical properties of the electro-active substrate did not affect device actuation. (C) 2011 Optical Society of America Y1 - 2011 SN - 0146-9592 VL - 36 IS - 8 SP - 1389 EP - 1391 PB - OPTICAL SOC AMER CY - WASHINGTON ER - TY - JOUR A1 - Döring, Sebastian A1 - Kollosche, Matthias A1 - Rabe, Torsten A1 - Stumpe, Joachim A1 - Kofod, Guggi T1 - Electrically tunable polymer DFB laser JF - Advanced materials Y1 - 2011 U6 - https://doi.org/10.1002/adma.201102465 SN - 0935-9648 VL - 23 IS - 37 SP - 4265 EP - 4269 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Stoyanov, Hristiyan A1 - Kollosche, Matthias A1 - Risse, Sebastian A1 - McCarthy, Denis N. A1 - Kofod, Guggi T1 - Elastic block copolymer nanocomposites with controlled interfacial interactions for artificial muscles with direct voltage control JF - Soft matter N2 - Soft, physically crosslinking, block copolymer elastomers were filled with surface-treated nanoparticles, in order to evaluate the possibility for improvement of their properties when used as soft dielectric actuators. The nanoparticles led to improvements in dielectric properties, however they also reinforced the elastomer matrix. Comparing dielectric spectra of composites with untreated and surface-treated particles showed a measurable influence of the surface on the dielectric loss behaviour for high filler amounts, strongly indicating an improved host-guest interaction for the surface-treated particles. Breakdown strength was measured using a test bench and was found to be in good agreement with the results from the actuation measurements. Actuation responses predicted by a model for prestrained actuators agreed well with measurements up to a filler amount of 20%(vol). Strong improvements in actuation behaviour were observed, with an optimum near 15%(vol) nanoparticles, corresponding to a reduction in electrical field of 27% for identical actuation strains. The use of physically crosslinking elastomer ensured the mechanical properties of the matrix elastomer were unchanged by nanoparticles effecting the crosslinking reaction, contrary to similar experiments performed with chemically crosslinking elastomers. This allows for a firm conclusion about the positive effects of surface-treated nanoparticles on actuation behavior. Y1 - 2011 U6 - https://doi.org/10.1039/c0sm00715c SN - 1744-683X SN - 1744-6848 VL - 7 IS - 1 SP - 194 EP - 202 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Ahnert, Karsten A1 - Abel, Markus A1 - Kollosche, Matthias A1 - Jorgensen, Per Jorgen A1 - Kofod, Guggi T1 - Soft capacitors for wave energy harvesting JF - Journal of materials chemistry N2 - Wave energy harvesting could be a substantial renewable energy source without impact on the global climate and ecology, yet practical attempts have struggled with the problems of wear and catastrophic failure. An innovative technology for ocean wave energy harvesting was recently proposed, based on the use of soft capacitors. This study presents a realistic theoretical and numerical model for the quantitative characterization of this harvesting method. Parameter regions with optimal behavior are found, and novel material descriptors are determined, which dramatically simplify analysis. The characteristics of currently available materials are evaluated, and found to merit a very conservative estimate of 10 years for raw material cost recovery. Y1 - 2011 U6 - https://doi.org/10.1039/c1jm12454d SN - 0959-9428 SN - 1364-5501 VL - 21 IS - 38 SP - 14492 EP - 14497 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Kollosche, Matthias A1 - Stoyanov, Hristiyan A1 - Laflamme, Simon A1 - Kofod, Guggi T1 - Strongly enhanced sensitivity in elastic capacitive strain sensors JF - Journal of materials chemistry N2 - Strain sensors based on dielectric elastomer capacitors function by the direct coupling of mechanical deformations with the capacitance. The coupling can be improved by enhancing the relative permittivity of the dielectric elastomer. Here, this is carried out through the grafting of conducting polymer (poly-aniline) to the elastomer backbone, leading to molecular composites. An enhancement in capacitance response of 46 times is observed. This could help to extend the possible range of miniaturization towards even smaller device features. Y1 - 2011 U6 - https://doi.org/10.1039/c0jm03786a SN - 0959-9428 VL - 21 IS - 23 SP - 8292 EP - 8294 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Kollosche, Matthias A1 - Zhu, Jian A1 - Suo, Zhigang A1 - Kofod, Guggi T1 - Complex interplay of nonlinear processes in dielectric elastomers JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - A combination of experiment and theory shows that dielectric elastomers exhibit complex interplay of nonlinear processes. Membranes of a dielectric elastomer are prepared in various states of prestretches by using rigid clamps and mechanical forces. Upon actuation by voltage, some membranes form wrinkles followed by snap-through instability, others form wrinkles without the snap-through instability, and still others fail by local instability without forming wrinkles. Membranes surviving these nonlinear processes are found to attain a constant dielectric strength, independent of the state of prestretches. Giant voltage-induced stretch of 3.6 is attained. Y1 - 2012 U6 - https://doi.org/10.1103/PhysRevE.85.051801 SN - 1539-3755 VL - 85 IS - 5 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Zhu, Jian A1 - Kollosche, Matthias A1 - Lu, Tongqing A1 - Kofod, Guggi A1 - Suo, Zhigang T1 - Two types of transitions to wrinkles in dielectric elastomers JF - Soft matter N2 - A membrane of a dielectric elastomer coated with compliant electrodes may form wrinkles as the applied voltage is ramped up. We present a combination of experiment and theory to investigate the transition to wrinkles using a clamped membrane subject to a constant force and a voltage ramp. Two types of transitions are identified. In type-I transition, the voltage-stretch curve is N-shaped, and flat and wrinkled regions coexist in separate areas of the membrane. The type-I transition progresses by nucleation of small wrinkled regions, followed by the growth of the wrinkled regions at the expense of the flat regions, until the entire membrane is wrinkled. By contrast, in type-II transition, the voltage-stretch curve is monotonic, and the entire flat membrane becomes wrinkled with no nucleation barrier. The two types of transitions are analogous to the first and the second order phase transitions. While the type-I transition is accompanied by a jump in the vertical displacement, type-II transition is accompanied by a continuous change in the vertical displacement. Such transitions may enable applications in muscle-like actuation and energy harvesting, where large deformation and large energy of conversion are desired. Y1 - 2012 U6 - https://doi.org/10.1039/c2sm26034d SN - 1744-683X VL - 8 IS - 34 SP - 8840 EP - 8846 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Laflamme, S. A1 - Kollosche, Matthias A1 - Connor, Jerome J. A1 - Kofod, Guggi T1 - Soft capacitive sensor for structural health monitoring of large-scale systems JF - Structural control & health monitorin N2 - Structural integrity of infrastructures can be preserved if damage is diagnosed, localized, and repaired in time. During the past decade, there has been a considerable effort to automate the process of structural health monitoring, which is complicated by the inherent large size of civil structures. Hence, a need has arisen to develop new approaches that enable more effective health monitoring. In this paper, a new sensing technique for damage localization on large civil structures is proposed. Specifically, changes in strain are detected using a capacitance sensor built with a soft, stretchable dielectric polymer with attached stretchable metal film electrodes. A change in strain causes a measurable change in the capacitance of the sensor, which can be directly monitored when the sensor is fixed to a structure. The proposed method is shown here to permit an accurate detection of cracks. The proposed system deploys a layer of dielectric polymer on the surface of a structural element, and regularly monitors any change in capacitance, giving in turn information about the structural state. The smart material is composed of inexpensive silicone elastomers, which make the monitoring system a promising application for large surfaces. Results from tests conducted on small- scale specimens showed that the technology is capable of detecting cracks, and tests conducted on large- size specimens demonstrated that several sensor patches organized on a sensor sheet are capable of localizing a crack. The sensor strain also exhibits a high correlation with the loss of stiffness. KW - large-scale system KW - structural health monitoring KW - strain monitoring KW - capacitive sensor KW - dielectric polymer KW - stretchable sensor Y1 - 2012 U6 - https://doi.org/10.1002/stc.426 SN - 1545-2263 VL - 19 IS - 1 SP - 70 EP - 81 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Stoyanov, Hristiyan A1 - Kollosche, Matthias A1 - Risse, Sebastian A1 - Wache, Remi A1 - Kofod, Guggi T1 - Soft conductive elastomer materials for stretchable electronics and voltage controlled artificial muscles JF - Advanced materials N2 - Block copolymer elastomer conductors (BEC) are mixtures of block copolymers grafted with conducting polymers, which are found to support very large strains, while retaining a high level of conductivity. These novel materials may find use in stretchable electronics. The use of BEC is demonstrated in a capacitive strain sensor and in an artificial muscle of the dielectric elastomer actuator type, supporting more than 100% actuation strain and capacity strain sensitivity up to 300%. KW - soft electrical connections KW - stretchable electronics KW - elastic conductor KW - compliant electrodes Y1 - 2013 U6 - https://doi.org/10.1002/adma.201202728 SN - 0935-9648 VL - 25 IS - 4 SP - 578 EP - 583 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Laflamme, Simon A1 - Kollosche, Matthias A1 - Connor, Jerome J. A1 - Kofod, Guggi T1 - Robust flexible capacitive surface sensor for structural health monitoring applications JF - Journal of engineering mechanics N2 - Early detection of possible defects in civil infrastructure is vital to ensuring timely maintenance and extending structure life expectancy. The authors recently proposed a novel method for structural health monitoring based on soft capacitors. The sensor consisted of an off-the-shelf flexible capacitor that could be easily deployed over large surfaces, the main advantages being cost-effectiveness, easy installation, and allowing simple signal processing. In this paper, a capacitive sensor with tailored mechanical and electrical properties is presented, resulting in greatly improved robustness while retaining measurement sensitivity. The sensor is fabricated from a thermoplastic elastomer mixed with titanium dioxide and sandwiched between conductive composite electrodes. Experimental verifications conducted on wood and concrete specimens demonstrate the improved robustness, as well as the ability of the sensing method to diagnose and locate strain. KW - Strain gages KW - Structural health monitoring KW - Monitoring KW - Probe instruments KW - Strain gauge KW - Structural health monitoring KW - Strain monitoring KW - Capacitive sensor KW - Dielectric polymer KW - Stretchable sensor KW - Flexible membrane KW - Sensing skin Y1 - 2013 U6 - https://doi.org/10.1061/(ASCE)EM.1943-7889.0000530 SN - 0733-9399 SN - 1943-7889 VL - 139 IS - 7 SP - 879 EP - 885 PB - American Society of Civil Engineers CY - Reston ER - TY - JOUR A1 - Saleem, H. A1 - Thunga, M. A1 - Kollosche, Matthias A1 - Kessler, M. R. A1 - Laflamme, S. T1 - Interfacial treatment effects on behavior of soft nano-composites for highly stretchable dielectrics JF - Polymer : the international journal for the science and technology of polymers N2 - We investigate the influence of interfacial treatment on the matrix filler interaction using a melt mixing process to fabricate robust and highly stretchable dielectrics. Silicone oil and silane coupling agent are studied as possible solutions to enhance the compatibility between the inorganic fillers and polymer matrix. Morphology, thermomechanical and dielectric behavior of the prepared specimens are studied. Results show that specimens filled with silicone oil coated particles have promising dielectric and thermal properties. The mechanical properties reveal a stiffness enhancement by 67% with a high strain at break of 900%. The relative permittivity of the specimens prepared with silicone oil increased by 45% as observed from the dielectric analysis. (C) 2014 Elsevier Ltd. All rights reserved. KW - Dielectric materials KW - Permittivity KW - Surface treatment Y1 - 2014 U6 - https://doi.org/10.1016/j.polymer.2014.06.054 SN - 0032-3861 SN - 1873-2291 VL - 55 IS - 17 SP - 4531 EP - 4537 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Carpi, Federico A1 - Anderson, Iain A1 - Bauer, Siegfried A1 - Frediani, Gabriele A1 - Gallone, Giuseppe A1 - Gei, Massimiliano A1 - Graaf, Christian A1 - Jean-Mistral, Claire A1 - Kaal, William A1 - Kofod, Guggi A1 - Kollosche, Matthias A1 - Kornbluh, Roy A1 - Lassen, Benny A1 - Matysek, Marc A1 - Michel, Silvain A1 - Nowak, Stephan A1 - Pei, Qibing A1 - Pelrine, Ron A1 - Rechenbach, Bjorn A1 - Rosset, Samuel A1 - Shea, Herbert T1 - Standards for dielectric elastomer transducers JF - Smart materials and structures N2 - Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. The rapid development of this field calls for the first standards, collecting guidelines on how to assess and compare the performance of materials and devices. This paper addresses this need, presenting standardized methods for material characterisation, device testing and performance measurement. These proposed standards are intended to have a general scope and a broad applicability to different material types and device configurations. Nevertheless, they also intentionally exclude some aspects where knowledge and/or consensus in the literature were deemed to be insufficient. This is a sign of a young and vital field, whose research development is expected to benefit from this effort towards standardisation. KW - standard KW - dielectric elastomer KW - actuator KW - electromechanically active polymer KW - EAP KW - electroactive polymer KW - transducer Y1 - 2015 U6 - https://doi.org/10.1088/0964-1726/24/10/105025 SN - 0964-1726 SN - 1361-665X VL - 24 IS - 10 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Saleem, Hussam A1 - Downey, Austin A1 - Laflamme, Simon A1 - Kollosche, Matthias A1 - Ubertini, Filippo T1 - Investigation of Dynamic Properties of a Novel Capacitive-based Sensing Skin for Nondestructive Testing JF - Materials evaluation N2 - A capacitive-based soft elastomeric strain sensor was recently developed by the authors for structural health monitoring applications. Arranged in a network configuration, the sensor becomes a sensing skin, where local deformations can be monitored over a global area. The sensor transduces a change in geometry into a measurable change in capacitance, which can be converted into strain using a previously developed electromechanical model. Prior studies have demonstrated limitations of this electromechanical model for dynamic excitations beyond 15 Hz, because of a loss in linearity in the sensor's response. In this paper, the dynamic behavior beyond 15 Hz is further studied, and a new version of the electromechanical model is proposed to accommodate dynamic strain measurements up to 40 Hz. This behavior is characterized by subjecting the sensor to a frequency sweep and identifying possible sources of nonlinearities beyond 15 Hz. Results show possible frequency dependence of the materials' Poisson's ratios, which are successfully modeled and integrated into the electromechanical model. This demonstrates that the proposed sensor can be used for monitoring and evaluation of structural responses up to 40 Hz, a range covering the vast majority of the dominating frequency responses of civil infrastructures. KW - nondestructive testing KW - structural health monitoring KW - soft elastomeric capacitor KW - capacitive sensor KW - vibration monitoring KW - sensing skin Y1 - 2015 SN - 0025-5327 VL - 73 IS - 10 SP - 1390 EP - 1397 PB - American Society for Nondestructive Testing CY - Columbus ER - TY - JOUR A1 - Kollosche, Matthias A1 - Kofod, Guggi A1 - Suo, Zhigang A1 - Zhu, Jian T1 - Temporal evolution and instability in a viscoelastic dielectric elastomer JF - Journal of the mechanics and physics of solids N2 - Dielectric elastomer transducers are being developed for applications in stretchable electronics, tunable optics, biomedical devices, and soft machines. These transducers exhibit highly nonlinear electromechanical behavior: a dielectric membrane under voltage can form wrinkles, undergo snap-through instability, and suffer electrical breakdown. We investigate temporal evolution and instability by conducting a large set of experiments under various prestretches and loading rates, and by developing a model that allows viscoelastic instability. We use the model to classify types of instability, and map the experimental observations according to prestretches and loading rates. The model describes the entire set of experimental observations. A new type of instability is discovered, which we call wrinkle-to-wrinkle transition. A flat membrane at a critical voltage forms wrinkles and then, at a second critical voltage, snaps into another state of winkles of a shorter wavelength. This study demonstrates that viscoelasticity is essential to the understanding of temporal evolution and instability of dielectric elastomers. (C) 2014 Elsevier Ltd. All rights reserved. KW - Dielectric elastomer KW - Viscoelasticity KW - Snap-through instability KW - Phase transition KW - Wrinkling Y1 - 2015 U6 - https://doi.org/10.1016/j.jmps.2014.11.013 SN - 0022-5096 SN - 1873-4782 VL - 76 SP - 47 EP - 64 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Ryabchun, Alexander A1 - Kollosche, Matthias A1 - Wegener, Michael A1 - Sakhno, Oksana T1 - Holographic Structuring of Elastomer Actuator: First True Monolithic Tunable Elastomer Optics JF - Advanced materials N2 - Volume diffraction gratings (VDGs) are inscribed selectively by diffusive introduction of benzophenone and subsequent UV-holographic structuring into an electroactive dielectric elastomer actuator (DEA), to afford a continuous voltage-controlled grating shift of 17%. The internal stress coupling of DEA and optical domain allows for a new generation of true monolithic tunable elastomer optics with voltage controlled properties. Y1 - 2016 U6 - https://doi.org/10.1002/adma.201602881 SN - 0935-9648 SN - 1521-4095 VL - 28 SP - 10217 EP - 10223 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Zehbe, Kerstin A1 - Kollosche, Matthias A1 - Lardong, Sebastian A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Taubert, Andreas T1 - Ionogels Based on Poly(methyl methacrylate) and Metal-Containing Ionic Liquids: Correlation between Structure and Mechanical and Electrical Properties JF - International journal of molecular sciences N2 - Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs. KW - microstructure KW - ionogels KW - ionic liquids KW - phase separation KW - mechanical properties KW - ionic conductivity Y1 - 2016 U6 - https://doi.org/10.3390/ijms17030391 SN - 1422-0067 VL - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Holländer, Lars A1 - Kossack, Wilhelm A1 - Kollosche, Matthias A1 - Wirges, Werner A1 - Kremer, Friedrich A1 - Gerhard, Reimund T1 - Influence of the remanent polarisation on the liquid crystal alignment in composite films of ferroelectric poly(vinylidene fluoride-trifluoroethylene) and a cyanobiphenyl-based liquid crystal JF - Liquid crystals : an international journal of science and technology N2 - Polymer-dispersed liquid crystals (PDLCs) of ferroelectric poly(vinylidene fluoride-trifluoroethylene) and nematic 4-cyano-4ʹ-n-hexylbiphenyl (6CB) or 4-cyano-4ʹ-n-pentylbiphenyl (5CB) were prepared to study the effect of the remanent polarisation of the polymer on the liquid crystal alignment. We measured the macroscopic alignment of the liquid crystal molecules in the thickness direction by means of Infrared Transition-Moment Orientational Analysis. Electrical poling at 100 V/µm caused an increased order parameter up to 0.15. After subsequent annealing above the nematic-to-isotropic phase-transition temperature, the order parameter was reduced to 0.02. Nevertheless, the order parameter was still higher than for non-poled film indicating a slight orientation in thickness direction. Both values are lower than those expected from model calculations. In agreement with dielectric measurements, we attribute this result to the shielding effect of mobile charge carriers within the liquid crystal inclusions. KW - Polymer-dispersed liquid crystal KW - ferroelectric polymer KW - remanent polarisation KW - liquid crystal alignment Y1 - 2016 U6 - https://doi.org/10.1080/02678292.2016.1185174 SN - 0267-8292 SN - 1366-5855 VL - 43 SP - 1514 EP - 1521 PB - Editions Rodopi BV CY - Abingdon ER - TY - JOUR A1 - Morgner, Frank A1 - Bennemann, Mark A1 - Cywiński, Piotr J. A1 - Kollosche, Matthias A1 - Górski, Krzysztof A1 - Pietraszkiewicz, Marek A1 - Geßner, André A1 - Löhmannsröben, Hans-Gerd T1 - Elastic FRET sensors for contactless pressure measurement JF - RSC Advances : an international journal to further the chemical sciences N2 - Contactless pressure monitoring based on Forster resonance energy transfer between donor/acceptor pairs immobilized within elastomers is demonstrated. The donor/acceptor energy transfer is employed by dispersing terbium(III) tris[(2-hydroxybenzoyl)-2-aminoethyl] amine complex (LLC, donor) and CdSe/ZnS quantum dots (QD655, acceptor) in styrene-ethylene/buthylene-styrene (SEBS) and poly(dimethylsiloxane) (PDMS). The continuous monitoring of QD luminescence showed a reversible intensity change as the pressure signal is alternated between two stable states indicating a pressure sensitivity of 6350 cps kPa(-1). Time-resolved measurements show the pressure impact on the FRET signal due to an increase of decay time (270 ms up to 420 ms) for the donor signal and parallel drop of decay time (170 mu s to 155 mu s) for the acceptor signal as the net pressure applied. The LLC/QD655 sensors enable a contactless readout as well as space resolved monitoring to enable miniaturization towards smaller integrated stretchable opto-electronics. Elastic FRET sensors can potentially lead to developing profitable analysis systems capable to outdo conventional wired electronic systems (inductive, capacitive, ultrasonic and photoelectric sensors) especially for point-of-care diagnostics, biological monitoring required for wearable electronics. Y1 - 2017 U6 - https://doi.org/10.1039/c7ra06379b SN - 2046-2069 VL - 7 SP - 50578 EP - 50583 PB - RSC Publishing CY - Cambridge ER -