PVDF as a Biocompatible Substrate for Microfluidic Fuel Cells
Date
2020-12-02
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-3359-6261
Type
Thesis
Degree Level
Masters
Abstract
A reliable, flexible, and biocompatible power source for implantable and wearable devices has always been one of the biggest challenges for medical device design engineers. Microfluidic fuel cells (MFCs) are one of the candidates to generate a constant and reliable energy. However, the aspects of this approach, such as use of expensive materials, limitation of achievable power density and biocompatibility, have not yet been fully addressed. These challenges have restricted the application of MFCs to lab-on-chip systems that are deemed to be promising for implantable medical devices.
Recently, porous materials such as natural papers and synthetic polymers (in the form of either nanofibers or porous membranes), when used as the MFC substrate, have shown that they can address the above-mentioned challenges. More importantly, these porous materials induce an inherent capillary flow in the fuel, eliminating the need of a pump. This may lead to an increased fuel efficiency and miniaturization of MFCs. However, the search for a porous biomaterial that displays high mechanical strength but remains flexible without degrading in a biological environment is not straightforward.
In this research, Polyvinylidene Fluoride (PVDF), a non-biodegradable, biocompatible, flexible, and inexpensive material, was investigated for the first time as a channel substrate in a dynamic state MFC. To achieve the desired porosity, flexibility, and material strength of the substrate, PVDF nanofibers were fabricated using the electrospinning technique. Furthermore, hydrophilic PVDF nanofibers were successfully achieved by oxygen plasma surface treatment.
The desired PVDF-based MFC was conceptualized using Axiomatic Design Theory (ADT) and FCBPSS (F: function, C: context, B: behavior, P: principle, SS: structure-state) methods. To investigate the electrochemical output of the designed PVDF-based MFC, a hydrophilic porous PVDF membrane was used as the substrate to induce a capillary action in the fuel (hydrogen peroxide). The PVDF-based MFC studied here successfully produced a power density of 0.158 mW/cm^2 at 0.08 V that is ~60% higher compared to the previous dynamic state paper-based biofuel cell reported in the literature. Moreover, the power density of MFC studied here is comparable to previous studies of static state single compartment MFCs using the same fuel type and concentration. Therefore, the results from this work demonstrate, for the first time, that the porous PVDF is a suitable material for the channel substrate in a dynamic state MFC.
The potential application of this cell, in medicine, is utilizing the hydrophilic porous PVDF in electrochemical, implantable, and wearable medical devices. This approach can also be applied to any self-powered point-of-care diagnostic system.
Description
Keywords
PVDF, nanofibers, MFC, capillary flow, biocompatible power source, microfluidics, fuel cell, porous membrane
Citation
Degree
Master of Science (M.Sc.)
Department
Mechanical Engineering
Program
Biomedical Engineering