Chemical Engineering Seminar

Abstract

Synthetic microswimmers, or active particles, are micro-scale objects that are capable of converting available energy, e.g., stored in chemical "fuel" or harvested from external sources, into directed motion. They are often thought as model systems for biological microscopic swimmers and have been offering new insights in the behavior of matter out of thermodynamic equilibrium. However, most synthetic microswimmers to date have been obtained from a very limited space of design parameters, and hence exhibit a limited range of functions compared to biological entities or larger machines. The challenge to expand the design space is then coupled to the incorporation of new materials and the development of new fabrication strategies, which enable programming and controlling the response of active particles under different conditions.

After a general introduction, I will propose two strategies that we are currently exploring in our laboratory. First, I will show that by choosing a photo-conductive coating that changes electrical conductivity under UV illumination, we can obtain Janus swimmers with programmable motility within light patterns. I will then show that the incorporation of thermo-responsive polymers, combined with the precise positioning of adaptive elements in the design of microswimmers, i.e., via directed assembly or nanoscale printing, enables the realization of reconfigurable microswimmers with multiple dynamical states, which are programmed during fabrication.

The rapid advancement in micro and nanoscale fabrication techniques and the ever-growing palette of available functional materials reveal an exciting future to develop complex active systems with programmable responses.

Biography

Lucio Isa is the ETH Zurich Full Professor of Soft Materials and Interfaces.

Lucio Isa was born in Milan (Italy) in 1979. He obtained a Masters degree (110/110 cum laude) in Nuclear Engineering from the Polytecnico di Milano (Italy) in 2004 and a PhD in Soft Matter Physics at the University of Edinburgh (UK) in 2008. After a short postdoctoral spell in Edinburgh, he moved to the Materials Department of ETH Zurich at the end of 2008 to work in the Laboratory for Surface Science and Technology, first as a Marie-Curie Fellow and then as a Swiss National Science Foundation (SNSF) Ambizione Fellow. In 2012 he was awarded a SNSF travel grant as visiting fellow at the Chemical Engineering Department of the University of California, Santa Barbara, USA. In September 2013 Lucio Isa became SNSF Assistant Professor, heading the Laboratory for Interfaces, Soft matter and Assembly in the Department of Materials at ETH Zurich. In April 2019, he was promoted to Associate Professor of Soft Materials and Interfaces and in 2024 to Full Professor.

Lucio Isa is a co-founder of Swiss Soft Days, an initiative aimed at creating a national network of scientists working in Soft Matter in Switzerland.