Effect of Dielectric Material and Package Stiffness on the Power Generation in a Packaged Triboelectric Energy Harvesting System for Total Knee Replacement

Abstract

The objectives of this study are to experimentally investigate the effects of the dielectric material and the package stiffness on the durability and the efficiency of a previously developed triboelectric-based instrumented knee implant prototype. The proposed smart knee implant may provide useful information about prosthesis health and its functionality after a total knee replacement (TKR) by routine monitoring of tibiofemoral load transfer without the need for any external power source. The triboelectric powered load sensing by the proposed TKR system needs to be functional throughout the entire life of a knee replacement. The power output of the triboelectric system depends on the surface charge generations and accumulations on its dielectric material, and the force that transmits through its housing into the tribo-materials. The properties of the dielectric material and the package stiffness can significantly influence the reliability of the proposed device. For such a TKR system, a compliant mechanism with the ideal material selection can improve its state of the art. We investigated the performance of three vertical contact mode triboelectric generators made with three different dielectric materials: PDMS, FEP, and PTFE. To investigate the effect of package stiffness, we tested two Ti-PDMS-Ti harvesters inside a polyethylene and a Ti6Al4V package. At 1500N of sinusoidal loads, the harvesters could generate 67.73 µW and 19.81 µW of mean apparent power in parallel and single connections in the polyethylene package, which was 32 and 17 times greater than the power recorded in the Ti assembly, respectively.

Hybrid triboelectric-piezoelectric nanogenerator for long-term load monitoring in total knee replacements

“…The relative voltage change remained virtually unchanged after 30 000 dynamic loading cycles, demonstrating the pressure sensor's outstanding mechanical and electrical stability. Our study on the proposed hybrid TPENG revealed minimal voltage deviation (RSD% below 3%) compared to previous studies (earlier studies reported variations with RSD% over 12% for PDMS [20]). In addition, we have introduced a mathematical model and numerical results that are in close agreement with experimental results.…”

“…They have been used to create motion or shock sensors [ 17 , 18 ] as well as load sensors. In our previous works [ 19 , 20 ], we examined the performance of TENGs employing different dielectric materials (polydimethylsiloxane (PDMS), fluorinated ethylene propylene (FEP), and polytetrafluoroethylene (PTFE)) with different patterns for self-powered load sensors for TKR at 1000–2000 N of simulated gait loading. One of the major obstacles hindering the practical use of TENGs is the issue of mechanical damage, which occurred for the PDMS layer of previous TENG designs.…”

Employing impedance spectroscopy to investigate electrical conduction mechanism in polymer composite blends containing conductive masterbatch: PP/EVA/ (PP-g-MA/MWCNTS)

“…Antistatic packaging by the modification of commercial polymers such as polyethylene (PE), PP, and poly (ethylene terephthalate) (PET) is a cost-effective way for solving this problem. [15][16][17] Blending these commercial polymers can improve the purposive properties for antistatic applications such as mechanical properties, film processing, and barrier ability properties. 18,19 Also, in polymer blend nanocomposites the adjustability of morphology due to the segregated structure that is originated from the formation of disperse-matrix or co-continuous morphologies and the tendency of conductive nanoparticles for localization in favorite phase is desirable in academic and industry for fabrication of conductive polymer nanocomposites with widespread applications.…”

Applications of Triboelectric Nanogenerators in Bone Tissue Engineering

“…[59] So far, many bonerelated sensing studies are knee implants due to the ease of integration of TENGs and implants. [60][61][62] These studies have explored design, fabrication, and optimization of smart knee implants by integrating TENGs. Ibrahim et al [60] laid the foundation of the smart knee implant using a triboelectric energy harvester.…”