1. David Perry The University of Warwick Electrochemistry and Interfaces Group Bias Modulated Scanning Ion Conductance Microscopy (BM-SICM)

2. Novak et al., Nature Methods 6, 279 (2009) SICM 2

3. Substrate Ag/AgCl Electrodes Tip-Substrate Separation Ionic Current Tip Diameter Tip Diameter 100 mM KCl V SICM 3

4. Substrate Ag/AgCl Electrodes Tip-Substrate Separation Ionic Current Tip Diameter Tip Diameter 100 mM KCl V SICM 4

5. Substrate Ag/AgCl Electrodes Tip-Substrate Separation Ionic Current Tip Diameter Tip Diameter 100 mM KCl V SICM 5

6. DC Current Tip Diameter Tip-Substrate Separation AC Amplitude Tip Diameter V Substrate Distance Modulated SICM 6

7. No physical oscillation of tip Can perform about 0V Potential to scan at wide range of frequencies Easier to model A Simple Alternative-Bias Modulation 7

8. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter McKelvey et al., Anal. Chem. 86, 3639−3646 (2014) 8

9. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 9

10. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 10

11. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 11

12. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 12

13. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 13

14. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 14

15. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 15

16. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 16

17. Bias Modulated SICM +10 mV -10 mV Bias DC Current 0 mV Substrate Tip Diameter 17

18. McKelvey et al., Anal. Chem. 86, 3639−3646 (2014) Experimental Approach Curves 18

19. McKelvey et al., Anal. Chem. 86, 3639−3646 (2014) Equivalent Circuit Model 19

20. McKelvey et al., Anal. Chem. 86, 3639−3646 (2014) Theoretical Approach Curves 20

21. Theoretical Experimental Experimental Vs. Theoretical 21

22. GOLD GLASS McKelvey et al., Anal. Chem. 86, 3639−3646 (2014) Distance Vs. Bias Modulated 22

23. AC Amplitude Set PointAC Phase Set Point Topographical Mapping of Calcite 23

24. SICM For Functional Imaging 24

25. Conclusions SICM is a powerful tool for non-contact imaging Improved feedback in the form of bias modulation Large feedback signal over a range of frequencies Good theoretical model Can scan topography using either AC amplitude or AC phase Extend SICM as a tool for functional imaging 25

26. Acknowledgements Dr. Kim McKelvey Sophie Kinnear Dr. Dmitry Momotenko Prof. Patrick Unwin 26