Acquiring Force Curves with the Asylum Cypher AFM

Acquiring Force Curves with the Asylum Cypher AFM These instructions are intended to be carried out immediately after acquisition of a topographical image in either acoustic or contact mode. Instructions for topographical imaging are not presented here. 1. If not already done, remove the tip from the surface of the sample by clicking Engage panel  Withdraw then Move to Pre-Engage 2. Put the microscope in contact mode by clicking Master panel  Imaging Mode  Contact 3. Calibrate tip: a. Click Thermal button along bottom of software to open the Thermal Graph window b. Click GetReal on right side of Thermal Graph window c. Enter the data for your probe (length, width, frequency, etc.) in Probe window d. Click Thermal Graph window  GetReal Calibration (may have to press it twice if it gives you an error). Your calibration results should resemble the figure below. e. Close Thermal Graph window 4. Set up the force curve display by clicking Master Panel  Force tab  Channels a. Under Graph1, select ZSensor for X and Force for Y. Also make sure Force is checked in the Save column. b. Uncheck any other Y values under Graph1 c. click Do it in Graph1 column 5. Set maximum force applied to sample: a. Click Master Panel  Force tab  Trigger Channel  select Force b. Master Panel  Force tab  Trigger Point is max force; default value depends on tip calibration 6. Put tip back on the surface by clicking Engage Panel  Start Tip Approach 7. Select point(s) on image to acquire force curves: a. Click Master Panel  Force tab  Go There tab  Check Show Markers b. Drag the crosshair marker on the image to the location where you would like to acquire a force curve (see figure below) c. Click Master Panel  Force tab  Go There tab  Pick Point d. Repeat b and c for all additional points on the image where you want to collect force curves. Note: after you pick the first point, the Pick Point button changes to That’s it! 2|Page 8. Acquiring force curves: a. Select the location where you want to acquire a force curve by clicking Master Panel  Force tab  Go There tab  Spot Number b. Move the AFM tip to the selected location by clicking Master Panel  Force tab  Go There tab  Go There. The location of the AFM tip is indicated by the red dot on the image. c. To acquire a force curve, click Master Panel  Force tab  Go There tab  Single Force. An example of a force curve is shown below. d. Repeat a-c for all locations where you want to acquire force curves 9. Fitting force curves to elasticity models: a. Click Menu bar  AFM Analysis  Master Force Panel b. Select your data folder in the window that pops up c. On the Display tab, click one of the force curves to open it d. On the Elastic tab, click the tab that corresponds to your desired model: Hertz, DMT, JKR, or Oliver-Pharr. On the Force Review Graph, the dashed black line shows the model’s fit to the data. e. Enter the Model Assumptions. The tip geometry and sample poisson are of particular importance. The results are shown on the right side of the Master Force Panel 3|Page 10. Exporting force curve data: a. Click Force Review Graph  Edit then click on the table that opens b. Click Menu bar  File  Save Table Copy 11. Acquiring force maps (force curves in a grid pattern over a surface): a. Click Master Panel  Fmap  Scan tab and set the desired parameters including scan size, XY velocity, force points and force lines. Enter a Base Name for your map. b. Click Do FMap button to acquire the map. 4|Page