1 Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585. Electronic address: chewch@nus.edu.sg.
2 Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK. Electronic address: yun.xu@imperial.ac.uk.
3 Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
4 Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585.