Ph.D Thesis

Ph.D StudentHorev Yehu David
SubjectHighly Stretchable Sensing Platforms for Future
Electronic Skin
DepartmentDepartment of Nanoscience and Nanotechnology
Supervisor PROF. Hossam Haick
Full Thesis textFull thesis text - English Version


Wearable devices have been attracting increased interest in human body motion detection and physiological signal monitoring, as these devices are of great importance in the development of prosthetic limbs, advanced robotics, and humane-machine interfaces; as they are embedded within a fabric or on a substrate. So far, it is still challenging to fabricate strain sensors that provide highly accurate and continuous motion recording while exerting minimal constraints and maintaining low interference with the body.

This research presents a novel device system for continuous monitoring of physiological markers, in order to monitor and characterize them both for medical, robotics, humane-machine, and other uses. For that, a novel wearable device for future electronic skin uses was developed. This device upholds a sensor array, along with self-power generating unit, and a self-healing ability.

Herein, this research presents a new free-standing ultrathin (varying from 300-10000nm), highly gas-permeable (33 mg/hr for ethanol), and lightweight nanofibrous based sensors that can be directly laminated onto the dynamic human skin for long periods of time. The device is made from covalently-grafted polyaniline (PANI) onto a stretchable elastomer nano-meshes. This intimate connection resulted in stable performance with excellent sustainability, linearity, durability, and low hysteresis. These devices demonstrate continuous interrogation of complex muscle activities and larger body motions while exerting minimal interference.

Continues monitoring is not complete without having sufficient power throughout time, hence this work also presents a novel approach for electrospun fabric based trib-electric nano-generators, with robust output of approximately 11mW/cm2; along with stretchable capacitors with good capacitive behavior and fast charge-discharge properties.

Moreover, a novel approach for self-healing devices, based on grafting PANI onto thin-films of self-healing polymer, thus opening a new functionality relevant to performance as a thin-film transistor.