Poonam Sundriyal
IIT Kanpur, Mechanical, Graduate Student
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The soft and flexible materials with shape and size adaption characteristics are gaining much attention for many applications, including wearable electronics, biomedical devices, microfluidic systems, tunable optics, soft robotics, and... more
The soft and flexible materials with shape and size adaption characteristics are gaining much attention for many applications, including wearable electronics, biomedical devices, microfluidic systems, tunable optics, soft robotics, and adaptive systems. Despite the several advancements in this area, the automated manufacturing and interface modification of these devices is still a major challenge. Here, we report 3D printing and laser for the rapid and scalable fabrication of dielectric elastomer actuators. The elastomer-based inks of dielectric matrix and electrodes were prepared with desirable rheology to obtain excellent print quality and required mechanical and electrical properties. This process can produce thin and ultrathin layers, porous structures, and interface modification of the device components. The device with printed elastomer patterns exhibited a breakdown strength of 40 V µm-1 at 8 % strain. The finite elemental simulation was also performed to determine the device...
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Sensory systems are available today at all length scales and formulate an important mandate in sustainability of environment and health. They use a wide spectrum of transduction mechanisms and signal conversion approaches with different... more
Sensory systems are available today at all length scales and formulate an important mandate in sustainability of environment and health. They use a wide spectrum of transduction mechanisms and signal conversion approaches with different levels of accuracy and rapidity. Sensors as deployed in various ranges of applications span from relatively simple temperature measurement bimetallic thermocouple structures to the detection of specific entities using advanced physical principles. The best example of sensors emanates from nature itself. Almost all living beings are blessed with sensory systems to sense and act to various environmental stimuli. There is a lot of inferential learning from such systems which can be translated to modern day sensor research. Within the environmental, chemical, and medical domains sensing can be carried out across a variety of length scales like the macroscale, microscale, or nanoscale. In a very organized manner a sensory system can be simplified into an ...
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Apart from micro- structure fabrication, ablation, lithography etc., lasers find a lot of utility in various areas like precision joining, device fabrication, local heat delivery for surface texturing and local change of microstructure... more
Apart from micro- structure fabrication, ablation, lithography etc., lasers find a lot of utility in various areas like precision joining, device fabrication, local heat delivery for surface texturing and local change of microstructure fabrication of standalone optical micro-devices (like microspheres, micro-prisms, micro-scale ring resonators, optical switches etc). There is a wide utility of such systems in chemical/ biochemical diagnostics and also communications where the standalone optical devices exist at a commercial scale but chip based devices with printed optics are necessary due to coupling issues between printed structures and external optics. This paper demonstrates a novel fabrication strategy used to join standalone optical fibres to microchip based printed optics using a simple SU8 drop. The fabrication process is deployed for fiber to fiber optical coupling and coupling between fiber and printed SU-8 waveguides. A CO2 laser is used to locally heat the coupling made up of SU8 material. Optimization of various dimensional parameters using design of experiments (DOE) on the bonded assembly has been performed as a function of laser power, speed, cycle control, spot size so on so forth. Exclusive optical [RF] modelling has been performed to estimate the transmissibility of the optical fibers bonded to each other on a surface with SU8. Our studies indicate the formation of a Whispering gallery mode (WGM) across the micro-droplet leading to high transmissibility of the signal. Through this work we have thus been able to develop a method of fabrication for optical coupling of standalone fibers or coupling of on-chip optics with off-chip illumination/detection.
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The additive manufacturing or 3- D printing technology has recently gained much attention in the industry and academia due to its ability to rapidly produce shape and size versatile 3-D patterns.[1-3] This technology has emerged as a... more
The additive manufacturing or 3- D printing technology has recently gained much attention in the industry and academia due to its ability to rapidly produce shape and size versatile 3-D patterns.[1-3] This technology has emerged as a smart manufacturing tool to develop flexible and miniaturized energy storage devices.[4-8] Here we report 3-D printed supercapacitors on the variety of flexible and stretchable substrates including Polydimethylsiloxane (PDMS), Polyurethane and Ecoflex. The supercapacitor electrodes in the planar configuration with 3- D architecture were printed over the substrates. The rGO- Silver nanoparticle ink was used to develop the conducting layer, CNT- MnO2 ink as a positive electrode, rGO- CNT ink as a negative electrode, and a gel electrolyte ink to form the full device. All the inks were successfully prepared in the water solution without using any additive or binders. The rheological properties of all inks were carefully controlled to achieve good print qual...
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The increasing focus on the environment-friendly electronics and requirement of easily disposable nonhazardous waste has introduced the cellulose paper as an attractive choice for energy storage devices. The disposal of commercially used... more
The increasing focus on the environment-friendly electronics and requirement of easily disposable nonhazardous waste has introduced the cellulose paper as an attractive choice for energy storage devices. The disposal of commercially used energy storage devices is a major problem, and it has a great threat to a sustainable environment. Paper-based flexible and low-cost energy storage devices are recently gaining much research attention and are highly needed in various industrial applications. This field is undergoing exciting innovations and holds enormous opportunities for further developments. In this chapter, we review the current developments of the paper-based energy storage devices, their fabrication methods, design strategies, application areas, and challenges for their further growth. An industrial/technological roadmap is also provided to help the readers to understand the future directions in this field.
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Inkjet printing is one of the most promising micro-manufacturing techniques to develop thin film and flexible electronics. The selective area deposition and efficient integration of all components of an electronic device on a flexible... more
Inkjet printing is one of the most promising micro-manufacturing techniques to develop thin film and flexible electronics. The selective area deposition and efficient integration of all components of an electronic device on a flexible substrate are major challenges for the existing flexible electronics field. Also, the wide spread of the portable electronics, with features such as compactness, lightweight, low cost, environment friendliness, and high-performance electronic devices, raises the demand for the more research attention in using smart manufacturing techniques to achieve the required performance of the flexible devices. Here, we have reported a micro-supercapacitor device on a filter paper substrate with ~8 μm thick electrode layer. The reduced graphene oxide (rGO) and rGO–MnO2 nanocomposite materials were converted to water-based printable inks using ethylene glycol and ethanol. The rGO ink was used to make the conducting patterns, while rGO–MnO2 nanocomposite ink is used...
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In the present work effect of 1% Magnesium (Mg) addition on Graphite (Gr) particulate Aluminum metal matrix composites (AMMCs) has been studied. Achieving good wettability and uniform distribution of particles in the metal matrix are... more
In the present work effect of 1% Magnesium (Mg) addition on Graphite (Gr) particulate Aluminum metal matrix composites (AMMCs) has been studied. Achieving good wettability and uniform distribution of particles in the metal matrix are major challenges for the fabrication of metal matrix composites and this problem can be overcome by two step-mixing stir casting method. Literature suggests that Mg is a strong surface agent which removes oxygen from the dispersoids surface so gas layers (which are responsible for the poor wettability) will be reduced hence wettability between the reinforcement particles and metal melt will be improved. So to obtain good wettability of solid particles with Aluminum (Al) melt 1% Mg was added in the Gr particles. AMMCs were prepared by varying Gr content as 2, 4 and 6 weight percentage of Al with and without addition of Mg. By comparing both of the composites, it was observed that Gr-1 wt.% Mg admixture reinforced composites have better mechanical propert...
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Sensory systems are available today at all length scales and formulate an important mandate in sustainability of environment and health. They use a wide spectrum of transduction mechanisms and signal conversion approaches with different... more
Sensory systems are available today at all length scales and formulate an important mandate in sustainability of environment and health. They use a wide spectrum of transduction mechanisms and signal conversion approaches with different levels of accuracy and rapidity. Sensors as deployed in various ranges of applications span from relatively simple temperature measurement bimetallic thermocouple structures to the detection of specific entities using advanced physical principles. The best example of sensors emanates from nature itself. Almost all living beings are blessed with sensory systems to sense and act to various environmental stimuli. There is a lot of inferential learning from such systems which can be translated to modern day sensor research. Within the environmental, chemical, and medical domains sensing can be carried out across a variety of length scales like the macroscale, microscale, or nanoscale. In a very organized manner a sensory system can be simplified into an ...
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ABSTRACT The green synthesis approach using ecofriendly biological precursors has gained world-wide popularity, reputation and recognition in the synthesis of several inorganic nanomaterials. This work demonstrates that a proper selection... more
ABSTRACT The green synthesis approach using ecofriendly biological precursors has gained world-wide popularity, reputation and recognition in the synthesis of several inorganic nanomaterials. This work demonstrates that a proper selection of biological precursor from the sustainable natural resources can effectively replace the commercial surfactant for fabrication of nanomaterials. Through this work, the green biotemplate Aloe vera plant extract has emerged as a better substitute of industrial surfactant poly(ethylene)glycol of molecular weight 8000 (PEG8000) in synthesis of ZnO nanorods using a simple sonoemulsion route. The colloidal growth of ZnO nanorods in PEG8000/Aloe vera -assisted sonoemulsion route has been elaborated in the context of relative supremacy of ultrasonic-assisted self-aggregation rate with steric-hindrance effect imposed by PEG8000/Aloe vera . The relative catalytic activity of PEG8000/Aloe vera synthesized ZnO nanorods, Co3O4 nanobelts and CuO nanorods in thermal decomposition of potassium perchlorate has been studied by thermo-gravimetric analysis and differential thermal analysis of pure potassium perchlorate and its mixture with nanoscale ZnO/Co3O4/CuO by 2% weight. The ZnO nanorods formulated through Aloe vera route demonstrated higher catalytic activity than that of ZnO nanorods prepared through PEG8000 route. The relative order of catalytic effect of nanoscale metal oxides in thermal decomposition of potassium perchlorate was found in descending order as CuO nanorods > Co3O4 nanobelts > ZnO nanorods.
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Research in the field of wearable and smart textiles and their development is rapidly growing due to the advancement of current and next-generation smart electronics era. Integrating electronics with characteristic properties of textiles... more
Research in the field of wearable and smart textiles and their development is rapidly growing due to the advancement of current and next-generation smart electronics era. Integrating electronics with characteristic properties of textiles like flexibility, permeability, durability, biocompatibility, and ease of use is the major challenge for the existing wearable electronics area. Silicon-based displays are expensive fixed and rigid, and hence they are not suitable for wearable and flexible electronics. So, we need its replacements without sacrificing the net result of the devices. This paper is focused on the development of OLEDs by several coatings of organic materials on wearable fabrics, modifications of fiber and fabric properties, selection of suitable substrate for OLEDs, printing, vapor deposition method of OLEDs coatings, and advantage and disadvantages of these methods. It also emphasizes the need for OLEDs encapsulation, surface planarization (for decreasing the surface ro...
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Electronic textiles have garnered significant attention as smart technology for next-generation wearable electronic devices. The existing power sources lack compatibility with wearable devices due to their limited flexibility, high cost,... more
Electronic textiles have garnered significant attention as smart technology for next-generation wearable electronic devices. The existing power sources lack compatibility with wearable devices due to their limited flexibility, high cost, and environment unfriendliness. In this work, we demonstrate bamboo fabric as a sustainable substrate for developing supercapacitor devices which can easily integrate to wearable electronics. The work demonstrates a replicable printing process wherein different metal oxide inks are directly printed over bamboo fabric substrates. The MnO2–NiCo2O4 is used as a positive electrode, rGO as a negative electrode, and LiCl/PVA gel as a solid-state electrolyte over the bamboo fabrics for the development of battery-supercapacitor hybrid device. The textile-based MnO2–NiCo2O4//rGO asymmetric supercapacitor displays excellent electrochemical performance with an overall high areal capacitance of 2.12 F/cm2 (1,766 F/g) at a current density of 2 mA/cm2, the excell...
The surface finish of the microelectromechanical systems substrate, particularly the ones that are deployed in chip-based optofluidic systems, is of utmost importance, and the overall surface finish helps in preventing light scattering... more
The surface finish of the microelectromechanical systems substrate, particularly the ones that are deployed in chip-based optofluidic systems, is of utmost importance, and the overall surface finish helps in preventing light scattering and associated losses. The proposed system is made up of a microchannel with a coating on its interior which acts as a cladding layer and possesses an air-like refractive index. The water-based solutions with refractive indices higher than the coating, when confined within such channels, act as waveguides with a refractive index difference which would allow grazing incidence at the solution film interface. The microchannel is fabricated over a piece of Si along <100> direction with the help of lithography and wet etching technique. After wet chemical etching of silicon, multiple pyramidal hillocks with overall large surface roughness is observed which are not appropriate for loss-free light transmission and cause various optical losses. So the o...