Department of Chemistry

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Jennifer Laaser

Assistant Professor

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G-12A CHVRN
Chevron Science Center
219 Parkman Avenue

Pittsburgh, PA 15260
412-383-0125

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Research Overview

The Laaser Lab is currently accepting new graduate students.

Physical Chemistry / Polymer Physics / Polymeric Materials

Polymers are all around us. From our clothing and our building materials to our medications and our foods, polymers - and particularly responsive polymers whose properties change with stimuli like heat, light, and pH -  are a versatile platform for many applications.

In the Laaser Lab, we are interested in developing a detailed understanding of how the molecular-scale chemistry of polymers connects to their macroscopic properties.

Our work is currently focused in two areas:

First, we are very interested in understanding ionic interactions between charged polymer chains.  In this area, one of the things we are exploring is a class of materials called complex coacervates, in which oppositely charged polymers come together in solution to form a hydrated, polymer-rich material with interesting viscoelastic properties.  We use controlled polymer syntheses to systematically vary the chemical compositions of the constituent polymers, and then use a variety of materials characterization techniques to understand how chemical properties like the charge density and hydrophobicity of the polymers affect the coacervates' properties.

In our work on charged polymers, we are also investigating a type of charged polymer system in which polymerization of ionic monomers can "lock" non-equilibrium ion distributions in place over long periods of time. These materials have potential applications in flexible electronic devices, and we are interested in understanding both how the chemical structure of the monomers and polymers affects the timescales on which ions can rearrange, and how chemical we might be able to use chemical triggers to release the ions from the chains on command.

Our second area of focus is on polymer networks.  In this area, one question we are particularly interested in is how forces are transmitted from the macroscopic scale to individual molecules when a material is deformed.  To investigate this problem, we synthesize and characterize polymers containing units called mechanophores that act as molecular-scale reporters of the force on the polymer chains.  By investigating how the activation of these mechanophores depends on the structure of the polymer network, we hope to understand both how networks respond to force, and how rational network design might be used to drive efficient force-triggered chemistry.

Students in our group gain broad exposure to a wide range of methods in polymer chemistry and polymer physics, including small-molecule organic synthesis, controlled radical polymerization, mechanical testing, microscopy, and even computational modelling.  Above all, we try to let the science guide us, and add new techniques to our toolbox as necessary to pursue the scientific questions we're interested in!

Awards

  • NSF CAREER, 2019
  • L’Oreal for Women in Science Postdoctoral Fellowship, 2014
  • AAAS Mass Media Fellowship, 2013
  • Casey Excellence in Research Award, UW-Madison, 2013
  • National Science Foundation Graduate Research Fellowship, 2008
  • Werner-Bergmann Prize, Yale University, 2008

Publications

“Role of Ligand Shell Density in the Diffusive Behavior of Nanoparticles in Hydrogels,” Moncure, Paige J.; Millstone, Jill E.; Laaser, Jennifer E.* J. Phys. Chem. B 2023, 127, 9366-9377
“Preferential Mechanochemical Activation of Short Chains in Bidisperse Triblock Elastomers,” Huo, Zijian; Watkins, Kasey F.; Jeong, Brandon C.; Statt, Antonia; Laaser, Jennifer E ACS Macro Letters 2023, 12 9, 1213-1217
“Effect of Polymer Composition and Morphology on Mechanochemical Activation in Nanostructured Triblock Copolymers,” Huo, Zijian; Arora, Swati; Kong, Victoria; Myrga, Brandon; Statt, Antonia; Laaser, Jennifer E Macromolecules 2023, 56 5, 1845-1854
“Computational Study of Mechanochemical Activation in Nanostructured Triblock Copolymers,” Huo, Zijian; Skala, Steven J; Falck, Lavinia; Laaser, Jennifer E; Statt, Antonia ACS Polymers Au 2022, 2 6, 467-477
“Relationship between Gel Mesh and Particle Size in Determining Nanoparticle Diffusion in Hydrogel Nanocomposites,” Moncure, Paige J; Simon, Zoe C; Millstone, Jill E; Laaser, Jennifer E J. Phys. Chem. B 2022, 126 22, 4132-4142
“Dynamics of Ion Locking in Doubly Polymerized Ionic Liquids,” Arora, Swati; Rozon, Julisa; Laaser, Jennifer E In: Macromolecules 2021, 54 13, 66466-6476
“Decoupling salt- and polymer-dependent dynamics in polyelectrolyte complex coacervates via salt addition,” Morin, Frances; Puppo, Marissa; Laaser, Jennifer E Soft Matter 2020, 17 5, 1223-1231
“Ion-Locking in Solid Polymer Electrolytes for Reconfigurable Gateless Lateral Graphene p-n Junctions,” Liang, Jierui; Xu, Ke; Arora, Swati; Laaser, Jennifer E; Fullerton-Shirey, Susan K Materials 2020, 13 5, 1089
“Triggerable Ion Release in Polymerized Ionic Liquids Containing Thermally Labile Diels–Alder Linkages,” Arora, Swati; Liang, Jierui; Fullerton-Shirey, Susan K; Laaser, Jennifer E ACS Materials Lett. 2020, 2 4, 331-335
“Charge-Density-Dominated Phase Behavior and Viscoelasticity of Polyelectrolyte Complex Coacervates,” Huang, Jun; Morin, Frances; Laaser, Jennifer E. Macromolecules 2019, 52 13, 4957-4967
“Equilibration of Micelle–Polyelectrolyte Complexes: Mechanistic Differences between Static and Annealed Charge Distributions,” Laaser, Jennifer E; McGovern, Michael; Jiang, Yaming; Lohmann, Elise; Reineke, Theresa M; Morse, David C; Dorfman, Kevin D; Lodge, Timothy P. J. Phys. Chem. B 2017, 121 17, 4631-4641
“Architecture-Dependent Stabilization of Polyelectrolyte Complexes between Polyanions and Cationic Triblock Terpolymer Micelles,” Laaser, Jennifer E; Lohmann, Elise; Jiang, Yaming; Reineke, Theresa M; Lodge, Timothy P. Macromolecules 2016, 49 17, 6644-6654
“Interpolyelectrolyte Complexes of Polycationic Micelles and Linear Polyanions: Structural Stability and Temporal Evolution,” J. E. Laaser, Y. Jiang, S. R. Petersen, T. M. Reineke, T. P. Lodge J. Phys. Chem. B 2015, 119, 15919-15928
“pH- and Ionic-Strength-Induced Contraction of Polybasic Micelles in Buffered Aqueous Solutions,” J. E. Laaser, Y. Jiang, D. Sprouse, T. M. Reineke, T. P. Lodge Macromolecules 2015, 48, 2677-2685
“Dye Self-Association Identified by Intermolecular Couplings Between Vibrational Modes as Revealed by Infrared Spectroscopy, and Implications for Electron Injection,” J. E. Laaser, J. R. Christianson, T. A. Oudenhoven, Y. Joo, P. Gopalan, J. R. Schmidt, M. T. Zanni J. Phys. Chem. C 2014, 118, 5854-5861
“Two-Dimensional Sum-Frequency Generation Reveals Structure and Dynamics of a Surface-Bound Peptide,” J. E. Laaser, D. R. Skoff, J.-J. Ho, Y. Joo, A. Serrano, J. D. Steinkruger, P. Gopalan, S. H. Gellman, M. T. Zanni J. Am. Chem. Soc. 2013, 136, 956-962
“Adding a Dimension to the Infrared Spectra of Interfaces using Heterodyne Detected 2D Sum-Frequency Generation (HD 2D SFG) Spectroscopy,” W. Xiong, J. E. Laaser, R. D. Mehlenbacher, M. T. Zanni Proc. Nat. Acad. Sci. 2011, 108, 20902-20907
“Time-Domain SFG Spectroscopy Using Mid-IR Pulse Shaping: Practical and Intrinsic Advantages,” J. E. Laaser, W. Xiong, M. T. Zanni J. Phys. Chem. B 2011, 115, 2536-2546
“Transient 2D IR Spectroscopy of Charge Injection in Dye-Sensitized Nanocrystalline Thim Films,” W. Xiong, J. E. Laaser, P. Paoprasert, R. A. Franking, R. J. Hamers, P. Gopalan, M. T. Zanni J. Am. Chem. Soc. 2009, 131, 18040-18041