Multifunctional Flexible Piezoelectrics for Wearable Medical Devices.
Lead Research Organisation:
University of Bath
Department Name: Mechanical Engineering
Abstract
The global market for medical wearable devices will reach $12.1 billion by 2021. In healthcare technologies, intelligent wearable devices provide an added value to diagnosis, treatment, patient monitoring and prevention. Diabetes is one of the most common chronic endocrine conditions that can develop at any stage of life and its incidence is increasing rapidly. According to the International Diabetes Federation, there are currently 415 million people worldwide with diabetes and this number is expected to grow up to 642 million in 2040, with an estimated 55% increase in 25 years.
Diabetic peripheral neuropathy is a common complication for people with diabetes, where the loss of sensation caused by nerve damage can make it difficult for people to feel when their foot is at risk of skin breakdown, which can result in foot ulcers forming. These ulcers can fail to heal and become infected over time; around 30% of patients with a diabetic foot ulcer may be at risk of lower limb amputation. Current best practice recommends patients perform daily monitoring of their feet supported by regular physical examination by trained specialists, which is time-consuming.
Here we propose the development of a novel self-powered wearable multifunctional sensing device that monitors the patient's posture. Whenever the pressure sensing inserts detect clinically dangerous foot pressure, a light signal and an audio alert are transmitted prompting the device user to offload the pressure from a particular region of their foot.
The multifunctional device will be composed of several layers of screen-printed functional ceramic inks on a flexible polymer substrate. A phosphor layer generates electroluminescent (EL) light and a piezoelectric layer generates sound and additionally harvests mechanical energy and convert it into EL light for feedback. A pyroelectric layer harvests thermal energy and converts that to electrical energy. Lead-free ferroelectric materials, such as barium titanate (BT) and potassium sodium niobate (KNN) based ceramics, will be printed and the dielectric, piezo and ferroelectric properties will be characterised. Different phosphors such as ZnS and ZnS:Cu will be fabricated to achieve optimum and uniform light emission. Coupling of the phosphor, piezoelectric and pyroelectric materials will result in a piezo-pyro-electro-luminescence device with simultaneous sound and light emission powered by energy harvesting of the external mechanical and thermal energy.
The project is in collaboration with DST Innovations, an expert company in printed electronics for flexible materials. The focus of DST is developing energy-efficient and environmentally safe technologies that can replace those used in today's electronic products. The company has expertise in developing lightweight, low powered and flexible lighting solution for large area lightings and will support the project by offering technical knowledge.
The main goals of this PhD project are the following:
Formulate and test the printability and performance of lead-free piezoelectric inks (BT-based, KNN) and phosphor inks (ZnS)
Formulate and test the conductive inks for optimum electrode structure
Fabricate multilayer devices using screen printing. Piezoelectric and phosphor layers will be printed individually and in combination, with and without electrodes.
Characterise the physical and electromechanical properties using impedance spectroscopy, piezoelectric, pyroelectric, ferroelectric, electroluminescence and surface roughness analysis
Develop and test the self-powered multifunctional wearable piezoelectric device
Diabetic peripheral neuropathy is a common complication for people with diabetes, where the loss of sensation caused by nerve damage can make it difficult for people to feel when their foot is at risk of skin breakdown, which can result in foot ulcers forming. These ulcers can fail to heal and become infected over time; around 30% of patients with a diabetic foot ulcer may be at risk of lower limb amputation. Current best practice recommends patients perform daily monitoring of their feet supported by regular physical examination by trained specialists, which is time-consuming.
Here we propose the development of a novel self-powered wearable multifunctional sensing device that monitors the patient's posture. Whenever the pressure sensing inserts detect clinically dangerous foot pressure, a light signal and an audio alert are transmitted prompting the device user to offload the pressure from a particular region of their foot.
The multifunctional device will be composed of several layers of screen-printed functional ceramic inks on a flexible polymer substrate. A phosphor layer generates electroluminescent (EL) light and a piezoelectric layer generates sound and additionally harvests mechanical energy and convert it into EL light for feedback. A pyroelectric layer harvests thermal energy and converts that to electrical energy. Lead-free ferroelectric materials, such as barium titanate (BT) and potassium sodium niobate (KNN) based ceramics, will be printed and the dielectric, piezo and ferroelectric properties will be characterised. Different phosphors such as ZnS and ZnS:Cu will be fabricated to achieve optimum and uniform light emission. Coupling of the phosphor, piezoelectric and pyroelectric materials will result in a piezo-pyro-electro-luminescence device with simultaneous sound and light emission powered by energy harvesting of the external mechanical and thermal energy.
The project is in collaboration with DST Innovations, an expert company in printed electronics for flexible materials. The focus of DST is developing energy-efficient and environmentally safe technologies that can replace those used in today's electronic products. The company has expertise in developing lightweight, low powered and flexible lighting solution for large area lightings and will support the project by offering technical knowledge.
The main goals of this PhD project are the following:
Formulate and test the printability and performance of lead-free piezoelectric inks (BT-based, KNN) and phosphor inks (ZnS)
Formulate and test the conductive inks for optimum electrode structure
Fabricate multilayer devices using screen printing. Piezoelectric and phosphor layers will be printed individually and in combination, with and without electrodes.
Characterise the physical and electromechanical properties using impedance spectroscopy, piezoelectric, pyroelectric, ferroelectric, electroluminescence and surface roughness analysis
Develop and test the self-powered multifunctional wearable piezoelectric device
Organisations
People |
ORCID iD |
| Hamideh Khanbareh (Primary Supervisor) | |
| Zois TSIKRITEAS (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513155/1 | 01/10/2018 | 30/09/2023 | |||
| 2319606 | Studentship | EP/R513155/1 | 20/01/2020 | 19/07/2023 | Zois TSIKRITEAS |
| Description | The studies associated with this award have can provide insights into the printability, rheological, morphological, dielectric and piezoelectric characteristics of micro-scale thin film particulate ferroelectric composites. More specifically, we have created and printed inks containing a mixture of DGMEA, DI7025, and BaTiO3 varied the amount of BaTiO3 filler in the ink. We have found that composites containing 40% BaTiO3 with a parallel layered structure exhibit the best performance. This information can be used to develop the next generation of thin film low-cost scalable sensors. |
| Exploitation Route | The outcomes of this study can be valuable to researchers and industry professionals interested in the production of microscale thin film printed sensors. The following are some ways that the findings could be taken forward and put to use: 1) Optimization of ink formulations: The study provides valuable information on the rheological behavior of ferroelectric inks and the effect of filler concentration on ink properties. Researchers and industry professionals could use this information to optimize ink formulations for screen-printing and other deposition methods. 2) Scale-up of production: The materials and manufacturing methodology outlined in the study are suitable for low cost semi-automatic or automatic pilot-line production processes. Industry professionals could use this information to scale-up production of ferroelectric composites using screen-printing. 3) Development of new applications: The study highlights the potential of ferroelectric composites for piezoelectric applications. Researchers could use this information to develop new applications for ferroelectric composites, such as sensors or actuators. 4) Further research: The study identifies areas for further research, such as the effect of printing parameters on the microstructure and properties of the composites. Researchers could use this information to conduct further research in this field and expand our understanding of ferroelectric composites. |
| Sectors | Electronics,Energy,Healthcare,Manufacturing, including Industrial Biotechology |