The importance of multifunctional devices which shall exploit specific properties of low dimensional structures increases constantly, with potential applications covering a wide range of industries from IT to medicine, the interest being fuelled by socio - economic challenges such as the necessity for “smarter” and more efficient artificial intelligence or addressing population aging and high costs of the healthcare system.
Consequently, employing complex architectures based on nanostructures and on materials with tailored properties represents an important path in developing new generations of functional devices such as soft robots, neuromorphic processors or advanced wearables which may both monitor chemical parameters (sweat or blood composition) and deliver various focused therapies.
The presentation focuses on describing such architectures developed in the Functional Nanostructures Laboratory of the National Institute of Materials Physics.
As functional elements nanowires or microscopic fibers were employed as electrodes for electrochemical sensors, as microscopic heaters for controlled drug delivery or as building blocks for biomimetic actuators. Nanowires are fabricated through chemical or electrochemical methods and used as active components for fabricating electronic devices such as diodes or field effect transistors. The fibers are fabricated using electrospinning or centrifugal/force spinning functionalization (e.g. electrical conductivity) being achieved through physical or chemical deposition.
Ionut Enculescu graduated at the Faculty of Physics of the University of Bucharest in 1995, his graduation work dealing with field effect transistors based on organic semiconductor materials. Further, IE became a research assistant at the National Institute of Materials Physics in Magurele, Romania and a PhD student at the Faculty of Physics of the University of Bucharest and continued his work in the field of Condensed Matter Physics, Semiconductors and Materials Science. Two problems were of interest namely influence of defects on piezoelectric properties of quartz crystals resonators and the electro-diffusion of ions through quartz crystals. After defending his PhD thesis in 2001, IE became a post-doc in a Marie Curie EU funded Research and Training Network (EUNITT- European Network on Ion Track Technologies) with work taking place in GSI Darmstadt and The. Angstrom Lab at Uppsala University. During this period IE added new professional skills ranging from working in large infrastructures (a heavy ion accelerator and a large clean room facility) to collaborating in extended research teams. Electrochemical deposition and clean room work were among the scientific skills acquired during this period. Moreover, the PI became familiar with characterization techniques such as scanning electron microscopy and X-ray microanalysis, the techniques being extremely important for the next part of his career. In 2004 IE returned to his home institute, the National Institute of Materials Physics, and founded a new research group in the Optics and spectroscopy Laboratory. The new group was focused onto developing nanostructures and devices based on nanostructures. During this time the institute received important new equipment based on an increase of funding from domestic and structural EU funds. The group grew and new themes were added to the existing ones, including here on one side electrospinning and on another side fabrication of electronic devices based on nanostructures using the new clean room facility in the Institute. In a further step the team led by IE succeeded in functionalizing micrometer and submicrometer fibers e.g. by covering with polyaniline and polypyrrole. By carefully choosing the experimental parameters the team led by IE obtained fiber webs with excellent electroactive properties. As it was proved in several papers in the last few years, such structures are excellent artificial muscles. The group led by IE was extended in 2016 with an important component – namely several experienced researchers attracted to the institute based on a structural funds financed grant. This allowed the addition of a biosensing/biochemistry component to the work leading to an important increase in complexity. Sensors/biosensors and drug delivery devices based on nano and microstructures were developed. It was found that biomimetic/bioinspired structures lead to excellent results in terms of both electroactivity and sensitivity.
Since 2013 IE is also the director of the National Institute of Materials Physics.