Polymer SPM Research

Overview of Haugstad research program

Our research interests involve three intertwined subjects:

  1. Scanning probe methods for studying condensed matter and microdevices.
  2. Surfaces, interfaces and films composed of polymers and/or small organic molecules.
  3. Energy dissipation at material interfaces.

Scanning probe studies of surfaces, interfaces, films and microdevices require the development of methodologies for data acquisition and interpretation. The interpretation of interactions between a scanning probe and condensed matter is aided by exploring parameter space: molecular weight, free volume, crystallinity, plasticizing molecules, etc. Most property-sensitive nanoprobes trigger energy dissipation (i.e., during interfacial sliding, rupture of contact, or cycling of compressive, tensile or shear strain). Polymeric/organic thin films often are employed to modify dissipation at interfaces (e.g., as lubricants or coatings).

Dominant mechanisms of energy dissipation in sliding friction on polymers have been identified as primary or secondary relaxations (i.e., dissipative rotational isomeric motions along the main chain or in side groups). Energy dissipation in amorphous domains (with rotational isomeric freedom) is strongly enhanced compared to highly crystalline domains, and a strong function of rate and temperature (akin to viscoelastic loss tangent). Water content also plays a large role in the case of hydrophilic polymers. In ongoing research, energy dissipation is being compared during shear, compression/tension and contact rupture.

Films studied to date range in thickness from nanometer- to micron-scale, comprised of solution-cast synthetic homopolymers of primarily hydrophobic or hydrophilic character, or biologically derived polymers like gelatin, physisorbed or chemisorbed to inorganic model substrates. Some work has involved more complex systems like polymer blends, polymer-polymer interfaces, block copolymers, or polymer-inorganic composites. Other work has examined plasma modification, crosslinking (network formation), or surfactant inclusion (e.g., emulsion delivery). Technological applications of interest include tribology (friction/lubrication/wear), coating/defects, biomedical insertion/interaction, organic semiconductor devices, adhesive/release media, and protein or waste water filtration.>

Analytical methods development includes several operating modes of scanning probe microscopy as follows.

  1. Sliding friction: variable velocity/temperature/humidity, calibration.
  2. Shear force modulation: low frequency, Fourier analysis.
  3. Rapid force curve mapping modes (pulsed force mode / peakforce tapping): energy dissipation during rupture of adhesive contact.
  4. Dynamic force: attractive/repulsive regimes, spatially resolved approach-retract curves, parameter space.
  5. Dynamic methods sensitive to surface potential and capacitance, such as Kelvin-probe force microscopy.
  6. Multifrequency methods: higher eigenmode imaging, contact resonance methods, single-pass EFM/KFM.

Physical topics have included

  • nanotribology (friction, wear, lubrication) and nanorheology on thin polymer films in the glass, rubber and melt regimes;
  • the effect of confinement and presence of surface on relaxational dynamics in polymer films, including spatial and energetic heterogeneities;
  • the effect of entanglement, crosslinking and aging on the structure and properties of polymeric materials;
  • the nature of energy dissipation during nanoscale mechanical perturbation (shear, tensile, compressive) and its relation to nanoscale structure (e.g., amorphous versus crystalline content);
  • adhesion hysteresis on polymeric materials, including rate and loading-history dependence;
  • nanocapillarity and the properties of confined liquids;
  • colloidal forces, interaction with solid and liquid media;
  • subsurface quantititive sensing (e.g., depth distribution of rigid objects in a soft matrix).

Much of this research relates to the activities of the Characterization Facility, including analytical services, education/training, or collaboration with industry. There is a dual theme: (1) development of scanning probe capabilities (measurement procedures, instrumentation, software), and (2) understanding mechanisms by which these methods probe materials surfaces and interfaces (structure, properties). Individual projects include both themes - methods development and interfacial materials research. The stimulus often originates in industry, with the research spanning both applied and fundamental issues.

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These selected publications exemplify (1) novel AFM methodologies, (2) applications useful to industry, and (3) ion beam analysis methods (RBS, PIXE) commonly utilized by both UMinn and other institutions. All are available via advanced training, collaboration and/or analytical services.

You may view the color images contained in some of pre-2001 papers below (those in poor-quality grayscale) by clicking on [images] or [figures in .xxx] where applicable. These are intended to provide more detailed versions of the published images. No captions are included and in many cases the figure numbers are not specified; the images load in the order that they appear in each respective paper.

Blending Polyurethane Thermosets Using Dynamic Urethane Exchange, J. L. Swartz, D. T. Sheppard, G. Haugstad, W. R. Dichtel, Macromolecules 54, 11126 (2021).

Holey Substrate-Directed Strain Patterning in Bilayer MoS2, Y. Zhang, M.-K. Choi, G. Haugstad, E. Tadmor, D. J. Flannigan, ACS Nano 15, 20253 (2021).

Use of Atomic Force Microscopy (AFM) to monitor surface crystallization in caffeine-oxalic acid (CAFOXA) cocrystal compacts, N. Kaur, G. Haugstad, R. Suryanarayanan, Int. J. Pharm. 609, 121196 (2021).

Spatial distribution of cell membrane protecting PEO-PPO-PEO block copolymer and non-protecting PEO homopolymer in lipid bilayer, M. Kim, F. Heinrich, G. Haugstad, G. Yu, G. Yu, S. Satija, W. Zhang, H. S. Seo, J. M. Metzger, S. Azarin, T. P. Lodge, B. J. Hackel, F. S. Bates, Langmuir 36, 3393 (2020).

Precursor selection in hybrid molecular beam epitaxy of alkaline-earth stannates, A. Prakash, T. Wang, R. Choudhary, G. Haugstad, W. L. Gladfelter, and B. Jalan, J. Vac. Sci. Technol. A 38, 063410 (2020).

Strong band gap reduction in highly mismatched alloy InAlBiAs grown by molecular beam epitaxy, J. Zhang, Y. Wang, G. Haugstad, and J. M. O. Zide, J. App. Phys. 126 095704 (2019).

Mechanical Deformation Distinguishes Tunneling Pathways in Molecular Junctions. Z. Xie,; I. Baldea, G. Haugstad, and C. D. Frisbie, J. Am. Chem. Soc. 141, 497 (2019).

Abrasive scanning with AFM on biocompatible polymers: measuring dry vs. swollen film thickness and probing properties, G. Haugstad and K. Wormuth, TechConnect Briefs 1, 16 (2018).

Defect-driven localization crossovers in MBE-grown La-doped SrSnO3 films, T. Wang, L. R. Thoutam, A. Prakash, W. Nunn, G. Haugstad and B. Jalan, Phys. Rev. Materials 1, 061601(R) (2017).

Adsorption-controlled growth and the influence of stoichiometry on electronic transport in hybrid molecular beam epitaxy-grown BaSnO3 films, A. Prakash, P. Xu, X. Wu, G. Haugstad, X. Wang, B. Jalan, J. Mater. Chem. C, 5, 5730 (2017).

Coexistence of Low Damping and Strong Magnetoelastic Coupling in Epitaxial Spinel Ferrite Thin Films, S. Emori, B. A. Gray, H.–M. Jeon, J. Peoples, M. Schmitt, K. Mahalingam, M. Hill, M. E. McConney, M. T. Gray, U. S. Alaan, A. C. Bornstein, P. Shafer, A. T. N’Diaye, E. Arenholz, G. Haugstad, K.-Y. Meng, F. Yang, D. Li, S. Mahat, D. G. Cahill, P. Dhagat, A. Jander, N. X. Sun, Y. Suzuki, B. M. Howe, Adv. Mater. 1701130 (2017).

Exceptionally Small Statistical Variations in the Transport Properties of Metal−Molecule−Metal Junctions Composed of 80 Oligophenylene Dithiol Molecules, Z. Xie, I. Baldea, A. T. Demissie, C. E. Smith, Y. Wu, G. Haugstad, C. D. Frisbie, J. Am. Chem. Soc.139, 5696 (2017). [full document in PDF]

Quantitative Surface Coverage Measurements of Self-Assembled Monolayers by Nuclear Reaction Analysis of Carbon-12, A. T. Demissie, G. Haugstad, C. D. Frisbie, J. Phys. Chem. Lett.7, 3477 (2016). [full document in PDF]

Defects, stoichiometry, and electronic transport in SrTiO3-epilayers: A high pressure oxygen sputter deposition study, P. Ambwani, P. Xu, G. Haugstad, J. S. Jeong, R. Deng, K. A. Mkhoyan, B. Jalan, C. Leighton,J. Appl. Phys.120, 055704 (2016). [full document in PDF]

Measuring the Thickness and Potential Profiles of the Space-Charge Layer at Organic/Organic Interfaces under Illumination and in the Dark by Scanning Kelvin Probe Microscopy, G. A. Rojas, Y. Wu, G. Haugstad, C. D. Frisbie, ACS Appl. Mater. Interfaces8, 5772 (2016). [full document in PDF]

Band alignment at epitaxial BaSnO3/SrTiO3(001) and BaSnO3/LaAlO3(001) heterojunctions, S. A. Chambers, T. C. Kaspar, A. Prakash, G. Haugstad, B. Jalan, Appl. Phys. Lett.108, 152104 (2016). [full document in PDF]

Strain Effects on the Work Function of An Organic Semiconductor, Y. Wu, A. Chew, G. Rojas, G. Sini, G. Haugstad, A. Belianinov, S. Kalinin, J.-L. Bredas, A. Salleo, C. D. Frisbie, Nat. Commun.7, 10270 (2016). [full document in PDF]

Growth of Thin, Anisotropic, Ï€-Conjugated Molecular Films by Step-Wise ‘Click’ Assembly of Molecular Building Blocks: Characterizing Reaction Yield, Surface Coverage, and Film Thickness vs. Addition Step Number, A. T. Demissie, G. Haugstad and C. D. Frisbie, J. Amer. Chem Soc.137, 8819-8828 (2015). [full document in PDF]

Characterization of Pebax angioplasty balloon surfaces with AFM, SEM, TEM, and SAXS, J. A. Warner, B. Forsyth, F. Zhou, J. Myers, C. Frethem and G. Haugstad, J. Biomed. Mat. Res. B , April 17 (2015). [full document in PDF]

Homoepitaxial growth modes in textured, polycrystalline ultrathin pentacene films on dielectrics, Y. Wu, V. Kalihari, G. Haugstad and C. D. Frisbie, Phys. Status Solidi B 252, 1291 (2015). [full document in PDF]

AFM probing of polymer/nano-filler interfacial adhesion and its correlation with bulk mechanical properties in a poly(ethylene terephthalate) nanocomposite, S. Aoyama, Y. T. Park, C. W. Macosko, T. Ougizawa and G. Haugstad, Langmuir 30, 12950 (2014). [full document in PDF]

Electronic Polarization at Pentacene/Polymer Dielectric Interfaces: Imaging Surface Potentials and Contact Potential Differences as a Function of Substrate Type, Growth Temperature, and Pentacene Microstructure, Y. Wu, G. Haugstad and C. D. Frisbie, J. Phys. Chem. C 118, 2487 (2014). [full document in PDF]

Real-time probe based quantitative determination of material properties at the nanoscale, G. Saraswat, P. Agarwal, G. Haugstad and M. V. Salapaka, Nanotechnology 24, 265706 (2013). [full document in PDF]

Strain-induced crack formations in PDMS/DXA drug collars, J.A. Warner, J.C. Polkinghorne, J. Gonerka, S. Meyer, B. Luo, C. Frethem and G. Haugstad, Acta Biomaterialia 9, 7335 (2013). [Online]

Atomic Force Microscopy: Understanding Basic Modes and Advanced Applications, G. Haugstad, Wiley (2012). Front Matter

Graphene fixed-end beam arrays based on mechanical exfoliation, P. Li, Z. You, G. Haugstad, T. Cui, Appl. Phys. Lett. 98, 253105 (2011). [abstract] [full document in PDF]

Characterization of Polymer Morphology in Polyurethane Foams Using Atomic Force Microscopy, Q. Lan and G. Haugstad, J. Appl. Polym. Sci. 121, 2644 (2011). [abstract] [full document in PDF]

Water Sorption Induced Transformations in Crystalline Solid Surfaces - Characterization by Atomic Force Microscopy, D. Chen, G. Haugstad, J. Z. Li and R. Suryanarayanan, J. Pharm. Sci. 99, 4032 (2010). [abstract] [full document in PDF]

Distinguishing Elastic Shear Deformation from Friction on the Surfaces of Molecular Crystals, V. Kalihari, G. Haugstad and C. D. Frisbie, Phys. Rev. Lett. 104, 086102 (2010). [abstract] [full document in PDF]

Multimodal Dynamic Imaging of Therapeutic Biomedical Coatings in Aqueous Medium, J. Dong, J. D. Foley, C. D. Frethem, R. A. Hoerr, M. J. Matuszewski, J. E. Puskas and G. Haugstad, Langmuir 25, 5442 (2009). [abstract] [full document in PDF]

Drug-eluting stent coatings, J. E. Puskas, L. G. Munoz-Robledo, R. A. Hoerr, J. Foley, S. P. Schmidt, M. Evancho-Chapman, J. Dong, C. Frethem and G. Haugstad, Wiley Interdisciplinary Reviews 1, 451 (2009). [abstract] [full document in PDF]

Environmental Digital Pulsed Force Mode AFM and Confocal Raman Microscopy in Biomedical Coatings Research, G. Haugstad and K. Wormuth, NSTI Nanotech Conference Proceedings, May 2009. [full document in PDF]

Well-aligned and suspended single-walled carbon nanotube film: Directed self-assembly, patterning, and characterization, M. Lu, M.-W. Jang, G. Haugstad, S. A. Campbell and T. Cui, App. Phys. Lett. 94, 261903 (2009). [abstract] [full document in PDF]

Strong Electronic Coupling in Two- Dimensional Assemblies of Colloidal PbSe Quantum Dots, K. J. Williams, W. A. Tisdale, K. S. Leschkies, G. Haugstad, D. J. Norris, E. S. Aydil, and X.-Y. Zhu, ACSnano 3, 1532 (2009). [abstract] [full document in PDF]

Observation of Unusual Homoepitaxy in Ultrathin Pentacene Films and Correlation with Surface Electrostatic Potential, V. Kalihari, D. J. Ellison, G. Haugstad and C. D. Frisbie, Adv. Mater. 21, 1 (2009). [abstract] [full document in PDF]

Grain Orientation Mapping of Polycrystalline Organic Semiconductor Films by Transverse Shear Microscopy, V. Kalihari, E. B. Tadmor, G. Haugstad and C. D. Frisbie, Adv. Mater. 20, 4033 (2008). [abstract] [full document in PDF]

Biofilm cohesiveness measurement using a novel AFM methodology, F. Ahimou, M. J. Semmens, P. J. Novak, G. Haugstad, Applied and Environmental Microbiology 73, 2897 (2007). [abstract] [full document in PDF]

Effect of protein, polysaccharide, and oxygen concentration profiles on biofilm cohesiveness, F. Ahimou, M. J. Semmens, G. Haugstad, P. J. Novak, Applied and Environmental Microbiology 73, 2905 (2007). [abstract] [full document in PDF]

Structural and Electrostatic Complexity at a Pentacene/Insulator Interface, K. Puntambekar, J. Dong, G. Haugstad and C. D. Frisbie, Adv. Funct. Mater. 16, 879 (2006). [abstract] [full document in PDF]

Tribology study of PVA contact lens in ionic aqueous environments, J. Dong and G. Haugstad, Proc. Am. Chem. Soc. National MeetingPolymer Preprints, Aug 2005. [full document in PDF]

Probing the morphology and tribo-response of nanostructured fluid films for personal care applications, G. Haugstad and A. Avery, NSTI Nanotech Conference Proceedings, May 2005. [full document in PDF]

Contrasting static-to-kinetic friction transitions on layers of an autophobically dewetted polymer film using Fourier-analyzed shear modulation force microscopy, G. Haugstad, Trib. Lett. 19, 49 (2005). [abstract] [full document in PDF]

Probing mesoscale molecular domains at surfaces of polymeric condensed matter with scanning force microscopy, G. Haugstad, Proc. Am. Chem. Soc. National MeetingPolymer Preprints, March 2004. [full document in PDF]

Scan-induced patterning and the glass transition in polymer films: temperature and rate dependence of plastic deformation at the nanometer scale", R. H. Schmidt, G. Haugstad, and W. L. Gladfelter, Langmuir 19, 10390 (2003). [abstract] [full document in PDF]

Scan-induced patterning in glassy polymer films: using scanning force microscopy to study plastic deformation at the nanometer length scale, R. H. Schmidt, G. Haugstad, and W. L. Gladfelter, Langmuir 19, 898 (2003). [abstract] [full document in PDF]

Probing swelling and molecular conformation on polymeric coatings for biocompatibility, G. Haugstad, Proc. Am. Chem. Soc. National MeetingPolymer Preprints44 (1), March 2003. [full document in PDF]

Shear modulation microscopy as an ultrasensitive probe of nonlinear response: stick-to-slide transitions and viscoplastic deformations of polymers, G. Haugstad, C. Dykstra and W. L. Gladfelter, Proc. Am. Chem. Soc. National MeetingPolymer Preprints44 (1), March 2003. [full document in PDF]

Viscoelasticity in nanoscale friction on thin polymer films, G. Haugstad, J. A. Hammerschmidt and W. L. Gladfelter, in: Interfacial Properties on the Submicron Scale, eds. J. Frommer and R. M. Overney, ACS Books 781, 230 (2001). [abstract] [full document in PDF]

Tip-sample interactions in dynamic force microscopy of polyvinyl alcohol films, G. Haugstad, W. L. Gladfelter and R. R. Jones, Polymer International 49, 427 (2000). [abstract] [figures in .ppt] [full document in PDF]

Imaging mechanisms in dynamic force microscopy of polymers, G. Haugstad, Microscopy Today (June issue, 1999). [figures in .ppt] [full document in PDF]

Probing polymer viscoelastic relaxations with temperature controlled friction force microscopy, J. A. Hammerschmidt, W. L. Gladfelter, G. Haugstad, Macromolecules 32, 3360 (1999). [abstract] [full document in PDF]

[Cover Feature] Mechanisms of dynamic force microscopy on polyvinyl alcohol: Region-specific non-contact and intermittent contact regimes, G. Haugstad and R. R. Jones, Ultramicroscopy 76, 77 (1999). [abstract] [figures in .ppt] [full document in PDF]

Correlation of nanowear patterns to viscoelastic response in a thin polystyrene melt, R. H. Schmidt, G. Haugstad and W. L. Gladfelter, Langmuir 15, 317 (1999). [abstract] [full document in PDF]

Correlating polymer viscoelastic properties with friction measures by scanning probe microscopy, J. A. Hammerschmidt, G. Haugstad, B. Moasser, R. R. Jones, and W. L. Gladfelter, in: Scanning Probe Microscopy of Polymers, eds. B. D. Ratner and V. V. Tsukruk, ACS Symposium Series, volume 694 (1998). [abstract]

Non-contact and intermittent contact scanning force microscopy of polyvinyl alcohol films, G. Haugstad, J. A. Hammerschmidt and W. L. Gladfelter, Polym. Prepr. 39, 1189 (1998). [full document in PDF]

Scanning force microscopy characterization of viscoelastic deformations induced by precontact attraction in a low crosslink density gelatin film, G. Haugstad, W. L. Gladfelter and R. R. Jones, Langmuir 14, 3944 (1998). [abstract][images] [full document in PDF]

Polymer viscoelastic properties measured by friction force microscopy, J. A. Hammerschmidt, B. Moasser, W. L. Gladfelter, G. Haugstad, R. R. Jones, Macromolecules29, 8996 (1996). [abstract] [full document in PDF]

Nanotribology on a polymer network film, G. Haugstad, W. L. Gladfelter and R. R. Jones, J. Vac. Sci. Technol. A 14, 1864 (1996). [abstract] [images] [full document in PDF]

Scanning force microscopy investigations of biopolymers, G. Haugstad, Trends Polymer Sci. 3, 353 (1995). [abstract] [full document in PDF]

Probing molecular relaxation on polymer surfaces with friction force microscopy, G. Haugstad, W. L. Gladfelter, E. B. Weberg, R. T. Weberg and R. R. Jones, Langmuir 11, 3473 (1995). [abstract] [images] [full document in PDF]

Scanning force microscopy of gelatin films in the dry, swollen and redried states, G. Haugstad, W. L. Gladfelter, E. B. Weberg, R. T. Weberg, T. D. Weatherill and R. R. Jones, Mat. Sci. Eng. C 3, 85 (1995). [abstract] [images] [full document in PDF]

Probing biopolymer films with scanning force methods, G. Haugstad, W. L. Gladfelter, E. B. Weberg, R. T. Weberg and T. D. Weatherill, Mat. Res. Soc. Symp. Proc. 355, 253 (1995). [abstract] [images] [full document in PDF]

Probing biopolymers with scanning force methods: adsorption, structure, properties and transformation of gelatin on mica, G. Haugstad, W. L. Gladfelter, E. B. Weberg, R. T. Weberg and T. D. Weatherill, Langmuir 10, 4295 (1994). [abstract] [images] [full document in PDF]

Force-displacement measurements in a beam-reflection scanning force microscope: calibration issues, G. Haugstad and W. L. Gladfelter, Ultramicroscopy 54, 31 (1994). [abstract] [full document in PDF]

Friction force microscopy of AgBr crystals: Ag0 rods and adsorbed gelatin films, G. Haugstad, W. L. Gladfelter and E. B. Weberg, Langmuir 9, 3717 (1993). [abstract] [images] [full document in PDF]

[Cover Feature] Atomic force microscopy of AgBr crystals and adsorbed gelatin films, G. Haugstad, W. L. Gladfelter, M. P. Keyes and E. B. Weberg, Langmuir 9, 1594 (1993). [abstract] [images] [full document in PDF]