Empowering today s nanoscale research with Peak Force Tapping

Transcription

1 Empowering today s nanoscale research with Peak Force Tapping Bede Pittenger, Andrea Slade and Chunzeng Li Bruker NanoSurfaces, Santa Barbara, CA, USA

2 A brief review of AFM imaging technology Mapping topography -> More information Contact mode (1986) Tapping Mode/Phase (1992) Force-Volume Mapping (~1992) Peak Force Tapping/PeakForce QNM (2010) PeakForce TUNA (2011) PeakForce KPFM (2012) 2

3 PFT Provides Excellent Spatial Resolution & Force Control 3

4 PeakForce QNM calculates sample properties directly from force curves The complete force curve from every interaction between tip and sample is analyzed in real-time, allowing: Feedback based on the peak force, protecting the tip and sample. Peak Force, Adhesion, Young s Modulus, Deformation, Dissipation mapped simultaneously with topography. Individual curves can be saved and analyzed offline (PeakForce Capture). (ii) 4

5 Rapid growth of Peak Force Tapping publications Topic Bio-related: cells/viruses/bacteria/plants paper count 110 Polymers 73 High Res Elect/Mag Bio Nanostructures: graphene/nanoparticles/nanofibers Electrical/Data Storage: MEMS/PV/Batteries high resolution: atoms/molecules Nanostruct Polymer Wide range of research areas ~75% are using PeakForce QNM for its unique data types Current count is ~340 publications 5

6 Peak Force Tapping publications are overrepresented in high impact journals Publication Impact Factor # papers Science Nature Nanotechnology Nature Methods Adv Mater Angew Chem Int Edit Nano Letters ACS Nano Adv Funct Mater Journal Of The Acs Plos Pathogens Small Curr Opin Colloid In Chem Sci Biomaterials Nature Communications Chem Mater The Plant Journal J Mater Chem Nanoscale Analytical Chemistry Biosens Bioelectron Biomacromolecules Carbon Polymer Chemistry Macromolecules Only the top ~10% of all publications have impact factors >=4 More than 30% of PFT publications are in the top 10% of journals As assigned by Journal Citation Reports (JCR) 6

7 Peak Force Tapping for straight forward, high quality images DNA Origami with Complex Curvatures in Three-Dimensional Space Peak Force Tapping provided quality images without disrupting the sample Keeps focus on research, not on characterization technique Han, D. et al., Science, 332(6027), pp

8 PeakForce QNM for high resolution imaging Green Chemistry Approach to Surface Decoration: Trimesic Acid Self- Assembly on HOPG Molecular resolution with PF- QNM to complement STM results Periodicity ~1.6nm Adhesion map provides resolution similar to PFT topography PFT is able to characterize multilayers, STM not PFT is more gentle than STM Observation of network disruption in images taken at 5 min intervals with STM No disruption from PFT over 48 hours PFT 50nm scan STM 25nm scan Adhesion 25nm scan Korolkov, V. V. et al., J. Phys. Chem. C, 116(21), pp

9 Sub-molecular mechanical mapping of protein flexibility Topography Low force topography Modulus Low force deformation Modulus mapping across individual br monomers revealed: Areas of high stiffness (low flexibility) = -helices. Areas of low stiffness (high flexibility) = intrahelical loops. E D C F B A Single br molecule E-F loops are most rigid structures at low forces, collapse at F~125pN 5nm Low force modulus Intrahelical Loops 5nm High force topography Rico, F. et al., Nano Letters, 11(9), pp Medalsy, I et al., Angew. Chem. Int. Ed., 50(50), pp

10 PeakForce QNM analysis of force curves Quantification of the interaction forces between metals and graphene by quantum chemical calculations and dynamic force measurements under ambient conditions. Study interaction force and peeling force between metal-coated probe & graphene Capture of the individual approach curves allowed comparison with DFT theory Lazar, P. et al., ACS nano, 7(2), pp

11 PeakForce QNM for quantitative results The use of the PeakForce quantitative nanomechanical mapping AFMbased method for high-resolution Young s modulus measurement of polymers. Compared PF-QNM modulus to instrumented nanoindentation tester (IIT) results for 12 polymers This work has shown that [PF- QNM] has the potential to be a useful supplement (with higher spatial resolution and surface sensitivity) to IIT for measuring the small-scale Young s modulus of a polymer surface. Recommends development of more contact models for even better accuracy Young, T.J. et al., Meas. Sci. and Tech., 22(12), p

12 PeakForce Tapping in Fluid AFM imaging of biological samples made easier. PeakForce Tapping makes imaging in fluid dramatically easier. Low imaging forces protect soft samples. No specialized probes. Eliminates need for cantilever tuning. No setpoint drifting (unlike TappingMode in fluid). AFM images were obtained in PeakForce Tapping mode in buffer using ScanAsyst Fluid+ probes (k ~0.7N/m). Sample courtesy of Dr. Wouter Roos & Prof. Gijs Wuite, Vrije Universiteit, Amsterdam, Netherlands. Scan Asyst automatic image optimization results in faster, more consistent results, regardless of user skill level. 12

13 PF-QNM of Amyloid Fibrils Probing Modulus Independent of Morphology Twisted Ribbon 2.3±0.6 GPa Different amyloid fibril morphologies will vary in rigidity but should have identical Young s modulus. PF-QNM was able to simultaneously: Identify fibril morphology. Quantitatively and accurately measure the modulus independent of fibril morphology. Helical Ribbon Nanotube-like 2.3±0.7 GPa 2.4±0.5 GPa Adamcik et al. (2012) Nanoscale, vol 4: /29/2014 Bruker Nano Surfaces Division MultiMode 8 AFM operated in air using ScanAsyst Air probes. 13

14 PF-QNM of Mammalian Cells The Role of Mechanical Forces in Disease BioScope Catalyst operated in fluid using ScanAsyst-Fluid probes. Control [Glyph] 15mM PF-QNM allowed researchers to monitor the effects of glyphosate on living human epidermal cells. Changes in cell stiffness were directly correlated to the appearance of cellular substructures. Heu et al. (2012) JSB, vol 178: /29/2014 Bruker Nano Surfaces Division 14

15 PF-QNM of Adhesion Events Molecular Recognition Mapping PF Topography PF Adhesion Bud Scars vandenla_beth/reproduction.htm. PF Modulus PF Adhesion PF-QNM enabled researchers to map the localization and mechanics of individual proteins of the surface of living yeast cells. Position of individual proteins mapped at unprecedented spatial resolution of ~4nm. Quantitative measurement of single NTA-Ni 2+ His) bond at ~306 ± 72pN. FV Modulus PF Adhesion Significantly higher spatial and temporal resolution over Force Volume imaging. Alsteens et al. (2012) Langmuir, vol 28: BioScope Catalyst operated in fluid using modified OTR4 probes. 1/29/2014 Bruker Nano Surfaces Division 15

16 Integrating PeakForce Tapping with TUNA (2011) PFTUNA is built on PF-QNM Additionally, PF-TUNA module has improved bandwidth: PeakForce Tapping Frequency : 1 khz -2 khz TUNA : >10x faster 16

17 PF-TUNA maps discriminate between components in heterogeneous samples AFM as an analysis tool for high-capacity sulfur cathodes for Li S batteries Sulfur rich & low conductivity Suspension Coated PVDF cathode Simultaneously measured property maps clearly allowed for distinction of different surface materials, distinguish different sample materials, which is not possible with the topography image only. Mapping before and after cycling showed that microstructure of cathodes strongly impacted battery performance SC-PVDF cathode found to be most stable Hiesgen, R. et al., Beilstein J. Nanotechnol., 4, pp

18 PeakForce TUNA for quantitative property measurement of V:Ti/SEO nanocomposite Quantitative Nanoelectric and Nanomechanical Properties of Nanostructured Hybrid Composites by PeakForce TUNA. [PF-TUNA] allows one to simultaneously map the topography, modulus, adhesion, and conductivity of advanced materials on delicate samples that cannot be imaged with conventional conductive AFM. Quantitative PF-TUNA current was correlated to the positions of individual particles in the topography image High adhesion and low current are observed at the nano particle boundaries rich in PS phase PF-TUNA current map was used to select locations for IV curves Gutierrez, J. et al., J. Phys. Chem. C, 118, pp

19 PF-TUNA for high-resolution mapping of current on polymer-nanotube composites Nanoscale investigation of the electrical properties in semiconductor polymer-carbon nanotube hybrid materials. Topography Current Carbon nanotube Topographic imaging can confirm that the CNTs are dispersed and the P3HT fibers grow perpendicular to the CNT High-res PF-TUNA current map indicates that the current is controlled by the spreading resistance beneath the tip Negligible lateral forces and normal force ~50pN make it possible to map current distribution over individual nanofibers Desbief, S. et al., Nanoscale, 4(8), pp

20 KPFM-Kelvin Probe Force Microscopy KPFM measures the work function difference of tip/sample. AM FM Amplitude-Modulation Frequency-Modulation Better spatial resolution Better accuracy Physical Review B 2005, 71(12)

21 Many Ways of Doing KPFM PeakForce KPFM in FM mode (2012) Tapping is limited to high k levers due to adhesive forces. Peak Force Tapping k is not. Both AM & FM KPFM improve with lower k Combines best resolution, sensitivity & accuracy *Except TM-FM, all are done in lift-mode. 21

22 PF-KPFM for quantitative characterization of work function Remove the Residual Additives toward Enhanced Efficiency with Higher Reproducibility in Polymer Solar Cells. PF-KPFM surface potential images (1μm scan) Pure polymer PF-KPFM shows that the methanol wash (Device C) increased the work function difference This reduced the electron injection barrier, leading to better device performance Ye, L. et al., J. Phys. Chem. C, 117(29), pp

23 PF-KPFM observations of corrosion over time Investigation of coating delamination on steels by surface topography and Volta potential difference Topographic images show swelling beneath the coating when the filament delaminates from the steels substrate Dark areas in surface potential are areas of growing filament acting as anodes, bright areas are acting as cathodes Anodic activity is not restricted to the mainstream direction of filament growth Future work expected to explore the details of these structures at higher resolution Topography 0.5hr 2hr cathodes 10hr Potential anodes AISI/SAE 1045 carbon steel with 300nm epoxy coating (90% humidity) Pan, T. et al., J. Solid State Electrochem., 17(4), pp

24 Summary: Peak Force Tapping Empowering Researchers with New Information Peak Force Tapping provides precise force control, enabling use of extremely low forces for routine high-resolution imaging of a wide range of samples. PeakForce QNM, TUNA, and KPFM enable quantitative nanoscale property maps to be captured simultaneously with topography data at high spatial and high temporal resolution. The adoption of Peak Force Tapping technology has seen rapid growth in many research areas supported by the ever increasing number of high impact publications since its release. 5nm 24

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