Faculty Publications
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Item Processing and investigation of mechanical characteristics on the polydimethylsiloxane/carbon black composites(Institute of Physics Publishing helen.craven@iop.org, 2019) Hiremath, S.; Sangamesh, R.; Kulkarni, S.M.The mechanical adaptability of elastomers has enormous potential in fields such as energy harvesting, micro electro mechanical system (MEMS), sensor, and actuator. A significant issue is to improve the mechanical features of the elastomeric base material by incorporating an appropriate filler. The elastomer Polydimethylsiloxane (PDMS) is reinforced with carbon black (CB) particles that affect mechanical characteristics (Tensile strength, compressive strength, tear strength, etc) and that have a critical impact on the efficiency of the device. The current research examines the mechanical characteristics of plain PDMS with a concentration of CB filler between 5% and 25%. A solution casting method is used to prepare the composite substrate and investigate the impacts of CB loading performance on tensile, compression, tear, and hardness testing. The outcome shows an improvement in mechanical characteristics due to CB material for Young's module as 1.64-3.84 MPa, ultimate tensile strength as 1.86-4.8 MPa, 3.67-4.81 MPa compressive module with the same compressive strength up to 40 percent strain. The tear strength of the PDMS/CB composites is improved by ?111 percent at 25 percent volume fraction of the CB. The composite hardness of PDMS/CB increases by about 30 percent of the plain PDMS material. Continuing with this, Additional mechanical characteristics of PDMS/CB composites on shear and bulk modules are reported. © 2019 IOP Publishing Ltd.Item Photomechanical actuation of polydimethylsiloxane/carbon black nanocomposite(Institution of Engineering and Technology jbristow@theiet.org, 2020) Hiremath, S.; Kulkarni, S.M.Materials such as carbon black (CB), carbon nanotube, graphene, etc. have been found to deform on exposure to the light source. Introducing these materials into polymers could convert them to photo-responsive composites. This is demonstrated by the experiment in which polydimethylsiloxane (PDMS) polymer containing CB nanofiller composites is prepared, and its photomechanical actuation from exposure to IR light source is recorded using a laser displacement sensor. The particle size analysis reveals the size of the CB, which is verified by the dynamic light scattering method. The UV-vis-IR spectrophotometer study shows that an increase in the light absorbance capacity of nanocomposites compared to the plain polymer. The PDMS/CB nanocomposite beam exhibited a significant deformation compared to plain PDMS. Deformation of the order of 10-11 mm is observed for a given IR source. The deformation found to have good repeatability but with some thermal hysteresis in cyclic actuation and de-actuation. © 2020 Institution of Engineering and Technology. All rights reserved.Item Investigation on dielectric properties of PDMS based nanocomposites(Elsevier B.V., 2021) Hiremath, S.; Kevin, A.M.; Manohar, S.B.S.; Kulkarni, S.M.Polymer nanocomposites have recently been used in applications for energy storage, sensors, and actuators. The polymer materials are gaining dielectric properties such as dielectric permittivity, electrical modulus, and conductivity. In the present study, nanocomposite material is prepared by a solution cast method incorporating carbon black particles into polydimethylsiloxane. The dielectric properties of PDMS/CB nanocomposites are investigated over broad frequency using an impedance analyzer. The polymer nanocomposite's dielectric permittivity is evaluated using the various empirical models available in the literature. Compared with other methods the Wiener model is very similar to the experimental findings. For the frequency range of 100 Hz-100kHz, the frequency-dependent and independent dielectric response was observed. Nanocomposite dielectric permittivity is improved marginally with the reinforcement of carbon black particles. The nanocomposite dielectric loss moves to the higher frequency, although the losses are small. It is proved that electrical modulus can reduce the effect of polarization of electrodes. Nanocomposite AC conductivity exhibits strong frequency dependence particularly in the higher frequency region of the vicinity. This behavior obeys the power law at critical frequency, which reveals the process of relaxing conductivity. The PDMS/CB nanocomposites power-law exponent is within a range of 0.48–0.57. Eventually, empirical and experimental inspections are the basis framework for designing electronic devices based on polymers. © 2020 Elsevier B.V.Item Progression and characterization of polydimethylsiloxane-carbon black nanocomposites for photothermal actuator applications(Elsevier B.V., 2021) Hiremath, S.; H, S.M.; Kulkarni, S.M.The new development of polymer-based actuators triggers the progress of nanocomposites. Polymer materials are currently used in sensors, microfluidic devices, electrical and thermal actuators, and energy harvesting applications due to ease of availability, excellent tolerable properties, and customizable properties. The polymer-based nanocomposite can be driven by various stimuli, which is the actuator's emerging field. Thus, photothermal actuation is a thurst area of research transforming light energy into mechanical energy through the polymer material. The photo-responsive material can be prepared and tested for photo-actuation by incorporating the nanoparticles into the polymer. The present work focuses on developing polydimethylsiloxane (PDMS) and carbon black (CB) nanocomposite. The objective here is to investigate the photothermal actuator's performance by illuminating the infrared (IR) light source and studying its most influential characteristics, such as absorbance, thermal conductivity, and the thermal expansion coefficient. The PDMS / CB nanocomposite absorbs the IR light and then increases temperature, which is finally transformed into a beam deflection. Responses are measured as a result of time deflection using the Laser displacement sensor. It is noted that the deflection of the nanocomposite beam is linearly increased during illumination with light while it is exponentially decreasing when the light is turned off. The proposed polymer nanocomposite is approximately deflected by 9 mm in the duration of 16 s duration. Furthermore, the experimental deflection of the photothermal actuator is very close to theoretical results. The nanocomposite PDMS / CB reveals that there is an increase in absorbance by increasing the filler content. The nanocomposite conductivity is 35.2 % higher than the base material. As well, the thermal expansion coefficient decreases with an increase in carbon black content. The photothermal actuator's development is an ongoing process in which the material parameter, actuator geometry, and many more are modified. As a result, the photothermal bending performed can provide a means for various light-driven applications. © 2020 Elsevier B.V.