Data Files Accompanying: “Lab on a Tip: Atomic Force Microscopy - Photothermal Infrared Spectroscopy of Atmospherically Relevant Organic/Inorganic Aerosol Particles in the Nanometer to Micrometer Size Range” Authors: Or, Victor, W., Estillore, Armando, D., Tivanski, Alexei, V., and Grassian, Vicki, H. Journal: Analyst Contact: Victor W. Or, vor@ucsd.edu, Department of Chemistry and Biochemistry, University of California San Diego . Vicki H. Grassian, vhgrassian@ucsd.edu, Department of Chemistry and Biochemistry, University of California, San Diego Cite as: Or, Victor, W., Estillore, Armando, D., Tivanski, Alexei, V., and Grassian, Vicki, H., (2018). Data from: Lab on a Tip: Atomic Force Microscopy - Photothermal Infrared Spectroscopy of Atmospherically Relevant Organic/Inorganic Aerosol Particles in the Nanometer to Micrometer Size Range. In Center for Aerosol Impacts on Chemistry of the Environment (CAICE). UC San Diego Library Digital Collections. https://doi.org/10.6075/J0F47MBF Description of File Types and Data: 3 file types (tif, txt, comma delimited text) are included. 6 types of data (particle height (tif,txt), particle phase (tif,txt), particle wavenumber map (tif,txt), particle frequency map (tif, txt), particle frequency-height ratio map (tif, txt), and PTIR (comma delimited text). Maps of particle height, phase, frequency, frequency-height-ratio map, and chemical map wavenumber intensity are held in corresponding .tif and .txt files. PTIR data is held in comma delimited text files. The .tif files are images of the particle, with scale bars shown in the x and y direction and the color denoting particle height, phase, frequency, frequency-to-height, or wavenumber intensity corresponding to the colormap. .txt files hold the data displayed in the .tif in a matrix. The data recorded (analyte height, analyte phase, chemical map), total height and width represented by the image, and units for data are specified at the top of the file. For chemical maps the PTIR wavenumber integrated over is specified in the file name. The comma delimited text files hold single point PTIR data with each column either containing the wavenumber, PTIR signal, or contact resonance frequency for the sample with the corresponding sample name. Description of File Names: Particle size in nm (usually) _ Chemical description_Mass-ratios(for two component particles)_ RHsometimes _ data type (height/phase/wavenumbermap/PTIR/frequency) Description of Column Names (PTIR spectra): Data type _ particle size (sometimes)_ chemical composition _ RH sometimes Abbreviations: 1to1: compounds were prepared in solutions with mass ratios of 1 to 1 PA: pimelic acid AS: ammonium sulfate Dry: size of particle when it was dried RH: relative humidity Methods:Model aerosol particles were analyzed by depositing aerosol particles onto substrates (ZnS or Si wafer). All chemicals used were purchased directly from the manufacturers, utilized without further purification, and included ammonium sulfate ((NH4)2SO4, >99%, Fischer Scientific), sodium chloride (NaCl, ≥99%, Fischer Scientific), glucose (C6H12O6, ≥99.0%, Sigma-Aldrich), sodium nitrate (NaNO3, ≥99%, Sigma-Aldrich), pimelic acid (C7H12O4, ≥99.0%, Sigma-Aldrich). Single component aerosol particles were generated from a 0.5 or 1% wt/v aqueous solution using ultrapure water prepared on site. (Thermo, Barnsted EasyPure- II; ≥18.2 MΩ cm resistivity). Aqueous solutions of compounds (and 1:1 %wt mixtures) listed above were atomized (TSI Inc., model 3076) to generate the aerosol particles. The aerosol particles were then sent through two diffusion dryers (TSI Inc., model 3062) at a flow rate of 1.5 lpm to reduce the RH to ca. 5% RH. Zinc sulfide (ZnS) and Si wafer sampling substrates (Ted Pella) were used to collect the aerosol particles by mounting the substrate in front of a differential mobility analyzer for 1-10 min. For relative humidity studies, hydrophobic substrates were prepared by cleaning Si wafer sampling substrates with isopropanol and coating in commercially available Rain-X. Samples were analyzed using a commercial nanoIR2 microscopy system (Anasys, Santa Barbara, CA, USA) using a laser power of up to 0.08 mW. Data was collected in Analysis Studio ( Anasys Instruments). AFM imaging of the laboratory generated aerosol particles were conducted at T = 298 K, and relative humidity (RH) of ~ 10-20% at ambient pressure. AFM images at a scan rate of 0.5 Hz using gold-coated silicon nitride probes (tip radius < 30 nm) with 0.07-0.4 and 1-7 N m-1 spring constants, and 13 ± 4 and 75 ± 15 kHz resonant frequencies, in contact mode or tapping mode, respectively. Photo-thermal IR spectra were collected with a spectral resolution of at least 8 cm-1, averaging 128 laser pulses per wavenumber. Chemical maps were collected at a scan rate of 0.05 Hz, averaging 16 times per pixel. For the water uptake measurements, the AFM head and the aerosol sample were contained within an environmental chamber system (Anasys, Santa Barbara, CA, USA) equipped with humidity and temperature sensor. The RH was adjusted by varying the ratio of wet and dry air controlled by a commercial dry air generator, across the range from 0 to 90% RH. RH sensor (Sensirion) inside the sample chamber was used to monitor the RH to within ±1%. To account for any particle deformation from impaction, aerosol particles sizes are reported as the diameter (D) of a sphere with equivalent volume (V): D= (6V/π)^(1/3). Growth factors determined by AFM were quantified by taking the ratio of the volume equivalent diameters for the particle at a particular RH to that of the dry particle. AFM generated images were analyzed and processed in Gwyddion, where images were flattened and cropped. Spectra were normalized and processed in Igor.