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HKBU Physics scholar set to uncover the world of cooperative molecular rotors

Professor Michel A Van Hove, Acting Head and Chair Professor of the Department of Physics, has recently been awarded a grant under the Collaborative Research Fund (CRF) 2015/16 of the Research Grants Council to conduct a group research project on cooperative molecular rotors.

On the theme of “Toward Integrated Machinery: Cooperative Molecular Rotors”, the project will be spearheaded by HKBU in collaboration with the City University of Hong Kong, The University of Hong Kong and the Hong Kong University of Science and Technology.

Professor Michel A Van Hove, Acting Head and Chair Professor of the Department of Physics, HKBU

Professor Michel A Van Hove, Acting Head and Chair Professor of the Department of Physics, HKBU

Here is the project summary from Professor Van Hove, the Project Co-ordinator:

CRF Project Title: Toward Integrated Machinery: Cooperative Molecular Rotors

Project Coordinator:  Professor Michel A Van Hove, Hong Kong Baptist University

Summary: This project aims to develop scientific understanding leading to the future exploitation of molecular machines, specifically rotor molecules. A molecular machine, whether natural or artificial, converts energy (such as thermal, electrical, chemical, magnetic, electromagnetic, or electronic energy) into mechanical motion that can then be used to accomplish useful work (such as transporting, turning, propelling, pushing, pulling, pumping or cutting). In particular, a molecular rotor produces rotational motion, as in bacterial flagellae, mechanical wheels and propellers.   Individual molecular rotors are already well understood, but there is a need to go further and explore how they can move together cooperatively, analogous to conventional mechanical gears and natural muscles that consist of multiple mechanically linked smaller “machines”: think of the many cogwheels in a mechanical watch, that need to turn in a well-coordinated fashion to show the time of day. Small atomic-scale phenomena and relatively large thermal energies add new and interesting opportunities in molecular machines, not available to classical machines.

Also important is the ability to combine the mechanical output motion of many single molecular machines in order to magnify their effect: this requires a network of mechanical linkages to funnel the combined mechanical motion to the desired application; think of an army of men joining their muscular forces to lift a heavy weight by means of well-linked ropes. Such mechanical linkages can also greatly help the challenge of thermal randomness at the molecular scale: thermal energy will make some molecular machines rotate in the wrong direction. Mechanically linking molecular machines will greatly help counteract this randomization by ensuring that the rotation will occur in the correct direction.

Of great interest is furthermore how collective motions propagate across a one-dimensional chain or multi-dimensional array of motor molecules, especially in the presence of defects, dissipation, etc., which will be largely inevitable in practical machinery: as in the mechanical watch, we want the rotation created in one point to be used in another point through a series of reliable linkages.   We will study these effects by surface science techniques, which allow manipulation and observation of individual molecules arranged in pairs, triplets, chains and arrays, in particular using scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Thereby, on a supporting crystalline substrate surface, each molecule can be fixed in a well-oriented and orderly fashion for individual observation even at the sub-molecular level.

We will investigate purpose-built molecules to explore the basic mechanisms of molecular linkages and coordinated motions. Through ab initio quantum modeling and molecular dynamics, we will be able to simulate and design correlated systems of molecules to understand and optimize their mechanical linkages and motions. Understanding these effects will make it possible in the future to design practical molecular machines operating at the nano- to microscale.

Longer-term Impact and Benefits:

This project has the potential of helping start the next hi-tech revolution, after the highly impactful introduction of microelectronics (radio and microwave communications, computers, smartphones) and optoelectronics (copiers, cameras, internet, solar panels, information displays). Nanomachinery could indeed become the next frontier for innovative technological developments, with wide applications such as nanoscale surgery, targeted drug delivery, selective genetic modification, biochips, microfluidics, as well as molecular-scale transport, pumping, sensing, robotics, and assembly. The impact of molecular machines on medicine and health is likely to be particularly beneficial.


About Collaborative Research Fund – Group Research Grant

Run by the Research Grants Council, the initiative is intended to encourage research groups in UGC-funded institutions to engage in collaborative research across disciplines and/or across institutions with a view to enhancing the research output of institutions in terms of the level of attainment, quantity, dimensions and/or speed.