Printed organic electronic device components from edible materials
- PDF / 764,302 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 85 Downloads / 261 Views
Printed organic electronic device components from edible materials Alex Keller1 and Marc in het Panhuis1,2 1
Soft Materials Group, School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia. 2
Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, AIIM Facility, University of Wollongong, Wollongong, NSW, 2522, Australia.
ABSTRACT The electrical and mechanical characteristics of ionic-covalent entanglement hydrogels consisting of combinations of the edible biopolymers gellan gum and gelatin were investigated. Impedance analysis and compression testing showed that these hydrogels (with water content = 97%) exhibited conductivity values of up to 13 mS/cm and compressive stress at failure values of up to 1.0 MPa. These are suitable characteristics for printed and mechanically robust wet device components.
INTRODUCTION Hydrogels are three dimensional hydrophilic polymer networks capable of swelling and storing up to 99% water by weight. When swollen these gels exhibit mechanical properties, such as elastic modulus, similar to that of natural tissue. As such, hydrogels have many promising applications in soft robotic component development, which seeks to replicate the natural movements observed in nature [1]. However, the applications of these gels have been inhibited by their weak mechanical behaviour and low inherent conductivity [2]. Therefore methods to improve the conductive and mechanical traits of these polymers need to be examined. Hydrogels which have been modified to increase their mechanical strength are known as tough hydrogels [3]. These tough gels can be produced by utilising slip-ring mechanisms, nanocomposite polymers or, as in our study, interpenetrating networks (IPN). IPNs are two uniformly mixed polymer networks which are independently cross-linked, resulting in a synergistic strengthening effect [4]. One class of IPNs is ionic-covalent entangled (ICE) hydrogels, which consists of an ionically cross-linked polymer enmeshed with a covalently cross-linked hydrogel [5,6]. These ICE gel polymers are advantageous in soft robotics as they possess high strength and water content, can be self-healing and are 3D printable [7]. However, due to low conductivities, these materials require modification to exhibit traits useful in soft robotics applications. Hydrogels can be tailored to become conductive in a number of ways, such as: through the addition of a secondary conducting polymer phase, the incorporation of redox centre functionalities or the addition of conductive fillers like nanotubes or graphite. However, electronic conductivity is inhibited by the presence of water, thus dehydration is required to obtain conductivities similar to semiconductors or metals[8]. The highest
electronically conductive hydrogel in the literature displayed a conductivity of 1 S/cm using 3,4ehtylenedioxythiophene in a double networked matrix a low water content of 72% [8]. Recently it has been demonstrated that ionic conductors can be used to develop simple, effe
Data Loading...
