This proposal concerns a study to examine the feasibility of constructing a blast-protection textile based on the highly unusual properties exhibited by helical auxetic yarns recently developed at the University of Exeter. An auxetic material is one which has a negative Poisson's ratio, (n). This means that, unlike conventional materials (with a positive Poisson's ratio) that get thinner when stretched, an auxetic material will get fatter. This unusual behaviour can be exploited to construct structures which can work in ways that have not previously been possible. This study will focus on further developing and exploiting the properties of helical fibre bundles with an auxetic geometry. The bundles developed at Exeter show auxetic functionality from zero to full strain; where the magnitude of the auxetic effect is also far superior. The bundles can also be produced in large quantities using conventional fabric weaving techniques. These features will enable the unique properties of auxetics to be utilised in a commercial application, - initially in the development of a new generation of smart blast protection fabrics. Bomb blast net curtains were invented for reducing hazards associated with explosion incidents. Glass is often the weakest part of a building, breaking at low pressures. Breakage can extend for many miles after a large explosion, and high velocity glass fragments are a major contributor to injuries in such incidents. Typically, many more people are hurt in explosions than are killed. By providing potential targets with window protection, laceration injuries are significantly reduced. Current blast curtain design favours the use of aramid nets. When an explosion occurs, the curtains are designed to billow out and capture a significant portion of the glass fragments. However in practice, the net fabric is often torn by the force of the blast. This is because the net filaments have to be made thin to keep the curtain from blocking light out. What is needed is a smart textile that allows light through but is also capable of containing the huge forces involved in an explosion and provides a barrier to flying debris. The project aims are to research how different auxetic fabrics and weaves respond to blast waves, and how far this behaviour can be used to mitigate the effects of explosions. It is intended that the study will culminate in the design, manufacture and test of several pre-production prototype textiles. There are several potential uses for auxetic textiles. One solution would involve the deployment of a smart auxetic fabric in a stretched open cell arrangement that would be translucent, enabling the curtains to be used at all times. In the event of an explosion, the curtain weave would be triggered to collapse by the initial shock wave, the fabric would shrink in resulting in a much tighter textile that would present an effective barrier to glass and other flying debris. Alternatively these yarns can be exploited to create a laminated textile which responds to the onset of a blast front by opening up arrays of pores in each layer. These let the blast wave pass through from one layer to the next, successively dispersing the energy it carries. Such textiles would not only be barriers to flying debris but also act to diminish the effects of the initial blast shock wave. Different parameters within the basic design may be altered to allow the system to be refined - these include fibre winding angles, fibre diameters and the basic characteristics of the materials used. The methodology used in the study will be to follow a project work programme broken down into a series of work packages, using milestones to focus activity and measure progress. Exeter and Auxetics Ltd will be responsible for the main body of research work throughout. Heathcoats ltd will be involved in weaving tests and the production of trial fabrics, and the PSDB will conduct the final blast testing of candidate textiles.

The rapid development of electronic devices and advanced sensors coupled with increasing concerns on global warming are driving requirements for portable, lightweight and flexible power sources to make our buildings smart and our portable devices independent from electricity grids. To this end, it is crucial to develop low-maintenance highly efficient energy sources that can provide local power, especially in ambient conditions. Thin-film photovoltaics offers such opportunity and are adaptable to any surface or device. Various ambient light photovoltaic technologies are investigated for harvesting energy from indoor light. Solar panels are traditionally made of photovoltaic devices and mostly rigid materials such as glass are used as substrates. However, this is not ideal and practical for indoor use. Recently, solar fabrics are being pursued for building integrated and interior energy harvesting. Photovoltaic devices integrated into textiles can also be used as portable power sources when coupled with bags, cloths, etc. However, more research into material development and manufacturing is needed to bring such technology closer to applications. To endow textiles with photovoltaic capability, it is essential to integrate the electronic functionality while maintaining the soft, stretchable properties of the textile, and the look and feel the end-user expects. Integrating such sophisticated function into textiles, however, is vastly different from fabrication of photovoltaic devices on the flat surfaces of glass or even plastic flexible substrates due to the porous, 3D structure of woven fabrics. This proposal addresses the manufacturing of new and emerging products related to the use of 2D materials for solar fabrics. The class of two-dimensional (2D) materials has expanded since since the isolation of graphene and now includes a great diversity of materials with various atomic structure and physical properties. Of particular interest for solar cells are the semiconducting transition metal di-chalcogenide (TMDC), with a band-gap ranging from visible to near infrared part of the spectrum (1.1 to 2.0 eV) and a significantly higher absorption coefficient per unit thickness (greater than Si, GaAs, and perovskites). These properties makes them extremely suitable for highly absorbing ultrathin photovoltaic devices for architectural and indoor applications and applications where lightweight or portability is highly desirable. The proposed research will develop textile-compatible manufacturing of solar fabrics based on 2D materials including semiconducting TMDCs as active layers and highly conductive graphene as electrodes. One key achievement is to develop manufacturing processes that easily translate from prototyping to production to enable solar textiles to become real products rather than proofs-of-concept. To date, the use of high performance photoactive materials on textiles has provided power conversion efficiency approaching 10%. Photovoltaic devices based on 2D materials using 2D/2D heterojunctions as active layers have been demonstrated, exhibiting external quantum efficiencies exceeding 50% and absorbance exceeding 90%. Achieving such high power conversion efficiencies on textiles, above 50% is the second key achievement for the investigations pursued here. This research will have impact and make a difference in the manufacturing area but also in other sectors such as healthcare, robotics and defence. The proposed research represents a technology leap towards autonomy and reliability of e-textile, reinforcing UK's position in e-textile markets. The proposed research has the potential to contribute various EPSRC prosperity outcomes such as "P1: Introduce the next generation of innovative and disruptive technologies", "P2: Ensure affordable solutions for national needs", "C2: Achieve transformational development and use of the Internet of Things" and "R1: Achieve energy security and efficiency".

Monitoring vital signs is essential in healthcare, and although there are currently several ways of doing so, either at the hospital environment or at home, conventional devices pose different challenges to their users, being bulky and uncomfortable, often complicated to operate by non-experts, and extremely expensive. With the Internet-of-Things (IoT)-driven device connectivity and technological advancements, as cellular connectivity is replaced by other types of wireless communications like Bluetooth, the fast-growing market of connected wearables also plays an important role in the emerging market of remote patient monitoring, since wearable devices also enable a hands-free operation and continuous recording of useful data. Integrating sensors for body temperature, breathing rate and cardiac activity directly on textiles would eliminate the inconvenience of uncomfortable hardware directly in contact with the human skin. This is very important in the case of electrocardiography, particularly when performed continuously, which requires the prolonged use of gel electrolytes to reduce the resistance between the skin and the electrode, often causing allergies and skin irritation. In addition to measuring temperature, cardiac activity and breathing rate, wearable sensors can also be used to track a person's body movements, which can also find applications in different fields, such as physiotherapy and rehabilitation. For instance, gait patterns can provide a lot of information about a patient's health. Moreover, these body movements and wasted body heat are often underestimated as a means to generate energy to power wearable devices. This project aims to innovative develop graphene-based and self-powered vital signs sensors fully integrated on textiles and with wireless communication capabilities. Such sensors offer a comfortable and almost imperceptible way of continuous monitoring, as opposed to heavy and bulky equipment currently in use for the same purpose. Exposed to external stimuli, such as mechanical deformations or variations in temperature, the conductivity of these textiles will change in a predictable way, and this will be explored for sensing purposes. Furthermore, these conducting textiles will also be used as electrodes for electrocardiography. A self-contained and environmentally friendly energy source based on a triboelectric nanogenerator, capable of harvesting energy from the movements of the user, will also be developed using similar materials and methods. This innovative approach of building the sensors directly on textiles will put the UK in the forefront in the field of continuous vital sign monitoring and remote healthcare and has the potential to generate numerous business opportunities. Allied to self-monitoring and self-care, with the rise of remote health monitoring there is an increasing need of practical and convenient vital sign monitoring devices with sensors that can be self-powered, easily integrated with conventional electronics and wireless communications, and simply operated in the palm of our hands, for instance, using a mobile phone. To ensure that this project is carried out successfully, a team comprising the PI, 2 postgraduate research students (PGRS) and one experienced postdoctoral research associate (PDRA) will be assembled, and will work closely with two industrial partners with expertise in the textile industry, (Centexbel, Belgium and Heathcoat, UK), and two academic partners from Skoltech, Russia, with expertise in electronics and wireless communications, and UCL, UK, with expertise in data processing, ideal to complement the expertise in materials, nanotechnology and physics of the team at Exeter.