Skin-printable and self-adhesive hydrogel electrodes for functional electrical stimulation therapyChen, Jia Xi Mary; Li, Terek; Saadatnia, Zia; Popovic, Milos R.; Naguib, Hani E.
doi: 10.1117/12.2663078pmid: N/A
From smart skins to human-machine interfaces, soft conductive materials have immense potential in wearable applications because of their conformity to the human skin. These materials may be adapted for healthcare devices and sensing functionalities, as well as for rehabilitation purposes like surface functional electrical stimulation (sFES), the process of inducing contractions in paralyzed muscles with electric currents. However, variabilities in muscle distribution among individuals pose new challenges against the development of wearable and personalized sFES platforms. To account for the intricate differences between muscles on different sites of the body, we developed a novel material to actualize stimulation electrodes that are adaptable to be of any shape and size, with self-adhesive properties to ensure conformity to body morphology and guarantee stimulation signal stability. The bio-based polymer of carboxymethyl cellulose is used for the hydrogel matrix due to its water solubility, along with poly(3,4- ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the conductive additive and tannic acid as the adhesive additive. A mild and biocompatible gelation method involving hydrogen bonds is implemented via the addition of phytic acid, forming the printed hydrogel for the bioelectronic interface within minutes. Compared with conventional stimulation electrodes, the printable hydrogel electrodes can induce muscle movement during sFES with better precision and accuracy.
Hybrid piezoelectric-magnetic, self-sensing actuator for vibration dampingLee, Ji Eun; Naguib, Hani
doi: 10.1117/12.2663411pmid: N/A
Stimuli-responsive soft actuators can actuate from an external stimulus. Compared to traditional actuators, these soft actuators offer advantages such as flexibility, conformability, better biomimicking ability, lower cost, and higher power to-weight ratio. These advantages are ideal for the vibration damping of transportation vehicles where there is a need for strong and lightweight designs whilst maintaining user comfort to encourage widespread public adoption. Piezoelectric materials are extensively used as sensors and actuators due to its piezoelectric property, and magnetic actuation is known for its accurate control. The current study investigates the development of a nanocomposite that can exhibit both piezoelectric and magnetic effects in terms of sensing and actuation, respectively. To achieve this, iron (III) oxide (Fe3O4) nanoparticles were attached to the surfaces of functionalized single walled carbon nanotubes (f-CNT), and the resulting nanofiller was embedded into a PVDF matrix. The Fe3O4 will provide magnetic actuation while the SWCNT will enhance the sensing performance of PVDF through its piezoelectric property. The proposed Fe3O4/f-CNT/PVDF showed effective vibration sensing and damping of excessive vibration on next generation of transportation vehicles for enhanced human safety and comfort. This research will assist in advancing multi stimuli-responsive materials and improve functionality and commerciality of soft smart material devices.
Environment-friendly bio-based epoxy resin/cellulose nanofiber film for triboelectric nanogenerator applicationKumar, Bijender; Adil, Samia; Song, Jongmin; Pham, Duc Hoa; Zhu, Shuaishuai; Kim, Jaehwan
doi: 10.1117/12.2658251pmid: N/A
The petroleum-based derived materials are used in industrial applications due to their specific properties. However, they are increasing environmental concerns because they produce toxic gases when disposed of and burned [1, 2]. Thus, biomass-derived epoxy resins have gained significant attention due to their low-cost, easy synthetic route, and environmentally friendly. CNF can be a promising approach for the future generation to design all-green materials with bio-mass-derived resins for various applications [3, 4]. This research aims to explore the strategies for hydrophilic CNF film to make it useable for high-performance applications. In this regard, the bio-based vanillin-derived epoxy resin was proposed to improve hydrophobicity of CNF film, making them ideal for TENG applications.
Object classification robot hand system using thermal conductivityPark, Heon Ick; Cha, Youngsu
doi: 10.1117/12.2657012pmid: N/A
In this paper, an object classification system by thermal conductivity is introduced. This system comprises a module of a flexible thermoelectric device (TED) and a resistance temperature detector sensor (RTD). The module is integrated with a silicone finger cot and is equipped onto a robot hand. Before grasping an object, the TED on the robot hand is heated to a specific temperature in degrees Celsius higher than room temperature. While the robot hand grasps an object, heat generated by the TED is transferred to the object. Sequentially, the RTD sensor detects heat variation of the object. And then, data from the sensor is computer-processed to classify the object. This object classification system successfully manipulates a real-time object identification by utilizing an intrinsic material property: thermal conductivity.
Effect of heat generation in PVDF based electro-active polymer actuatorsKalel, Sudarshan; Wang, Wei-Chih
doi: 10.1117/12.2664899pmid: N/A
Many of the electroactive polymers are dielectric and often demand high operating voltages for actuation (<<10 MV/m). These EAP-based actuators require metallic electrode layers on the surface to apply the voltage. Due to high operating voltage, heat is produced at the surface of electrodes due to resistive heating and dielectric losses in polymer material. In the case of actuators based on active and passive layer configurations with metallic electrodes, this heat could affect the performance, as the generated heat is transferred between the layers. In the present work, a PVDF terpolymer and Kapton tape-based bilayer actuator is developed, and simulation and experimental study are carried out to check the effect of DC high voltages on heat production within layers. The contribution of this heat to the bending of the actuator is also analyzed. It is found that significant heat is generated that can affect deflection process of the EAP actuator. The total electromechanical bending deflection produced at the E-field of 20 MV/m is ~80 degrees whereas deflection due heat generated at this voltage is ~15 degrees. Hence, the total deflection produced can be claimed as a combination of thermal and electro-mechanical effects.
Developing a novel electro-optic scanner for potential micro display and head-mounted display applicationWang, Wei-Chih; Ghorapade, Vinayak; Kalel, Sudarshan; Estroff, Benjamin; Chen, Chiali; Hsu, Yu Yang
doi: 10.1117/12.2664900pmid: N/A
Light beam deflectors and scanners have great potential in displays and microscopy for industrial and medical applications. A liquid crystal (LC) material that responds to external stimuli is a promising candidate for such applications. The goal of the proposed work is to create a miniature light scanning device without any moving parts using integrated electro-optic(EO) LC material. The design is based on changing the propagation direction of a light beam when it is incident to an electro-optic medium with a voltage-controlled index of refraction. The current design consists of two horizontal LC cell cascaded prisms (active Prism I and II) for horizontal beam deflection and a vertical prism (passive) at the end of the horizontal stage for vertical beam deflection. In the present work, a mathematical model and simulation study is conducted on the proposed design to achieve 2D deflection of the beam (λ=632 nm). The optimized prism or apex angle of active prisms I and II are 63 and 56.7 respectively, whereas the prism angle of the passive prism is 37.5. With an incident beam angle (θ1) of 9 at the entry of prism I, maximum horizontal deflection of >36 and maximum vertical deflection of >13 is achieved through theoretical and simulation study.
3D-printed flexural sensor devices for smart packaging of agrifood productsVasileiadis, A.; Exarchos, D. A.; Tsapara, G.; Dalla, P. T.; Matikas, T. E.
doi: 10.1117/12.2663134pmid: N/A
Smart packaging of food products is a new promising technology aiming to the preservation of consumer’s health and safety while prolonging the products’ self-life in transport and mass storage. Smart packaging can be applied by using chemical and/or biological sensors for monitoring indicators associated with bacterial growth and spoilage, as well as pathogen contamination. Poultry meat is a nutrient-rich matrix which supports the growth of various micro-organisms and the extended storage time can allow the proliferation of different microbial species on meat surfaces. The nature of the packaging approaches and storage factors can dictate the nature of the spoilage that transpires, with respect to the dominant microflora of the end-product. In the present study an innovative approach is explored for the development of cost-effective 3D-printed biosensors for monitoring known indicators associated with bacterial growth and spoilage in poultry meat. Spoilage was also independently measured using MSI and FT-IR spectroscopic methods. The development of a protocol for pathogen screening was also investigated with real-time polymerase chain reactions (qPCR).
Front Matter: Volume 12485doi: 10.1117/12.2682950pmid: N/A
This PDF file contains the front matter associated with SPIE Proceedings Volume 12485, including the Title Page, Copyright information, Table of Contents and Conference Committee lists.
Stretchable piezoelectric polymer blend for dynamic stress and strain sensingTu, Ruowen; Sodano, Henry A.
doi: 10.1117/12.2656945pmid: N/A
Flexible and stretchable stress and strain sensing materials have gained a lot of research interest recently as the development of wearable sensors for health monitoring, motion capturing and soft robotics. In these applications where dynamic stress and strain are common, piezoelectricity becomes a suitable sensing mechanism due to its fast response and high sensitivity. Existing research on flexible piezoelectric materials includes nanocomposites and sandwich composites made of piezoelectric fillers and elastomers. However, the giant modulus mismatch between the two distinct phases makes nanocomposites or sandwich materials prone to inaccurate sensing under large strains due to the weak stress transfer efficiency. In this research, polyvinylidene fluoride (PVDF) and unvulcanized nitrile rubber (NBR) are both dissolved in N,N-dimethylformamide (DMF) and then precipitation printed into a water bath to produce PVDF/NBR polymer blends. The blends are further vulcanized via hot pressing. The resulting blends exhibit polar phases of PVDF, highly uniform blend morphology, as well as excellent stretchability. As a stretchable sensor, the PVDF/NBR (2:8) shows consistent open circuit voltage-strain and open circuit voltage-stress relationships, as well as a high operating strain range up to 70%. Therefore, the PVDF/NBR blend can be used as a promising dynamic stress/strain sensing material for wearable sensors or soft robotic sensors.
A multiplayer virtual reality platform to evaluate electronic travel aid performance for persons with blindness and low visionRicci, Fabiana Sofia; Boldini, Alain; Rizzo, John-Ross; Porfiri, Maurizio
doi: 10.1117/12.2658453pmid: N/A
The prevalence of blindness and low vision is skyrocketing as the population ages. Independent, efficient, and safe navigation for persons with blindess and low vision requires hard work, practice, and development of strong orientation and mobility skills. In this vein, orientation and mobility training provides tools to familiarize oneself with new environments and maintain an independent lifestyle. In recent years, orientation and mobility training has adopted electronic travel aids, smart devices developed to assist those with blindness and low vision during navigation. However, learning how to use an electronic travel aid in orientation and mobility training sessions may prove dangerous for, as an end user. Early in use, the end user may misinterpret the information provided by the electronic travel aid. In fact, there may be a shallow learning curve during initial implementation. To this end, we built a multiplayer virtual reality platform to simulate an orientation and mobility training, involving trainer and trainee, for practicing with an electronic travel aid in a controlled, safe but realistic environment. We interfaced the virtual reality platform with a custom electronic travel aid created by our team. The electronic travel aid consists of a specially designed camera on a backpack and a haptic belt, along with software that can relays information about the location of near obstacles in the virtual environment through spatiotopic vibrotactile stimulation of the abdomen. In the virtual environment, the trainer can instruct the trainee in the use of the electronic travel aid while navigating complex urban environments. The efficacy of the communication between trainer and trainee towards teaching the correct use of the electronic travel aid and its performance in assisting navigation will be evaluated through series of systematic experiments.