The Hallinan Lab studies polymers for advanced energy sustainability. This is increasingly important as petroleum usage is decreased and as intermittent renewable sources, such as wind and solar energy, become more prevalent. Significant improvements in safety, cost, and energy density of commercial batteries are possible by replacing the currently used liquid electrolyte with solid (polymer) electrolyte. Other areas of energy sustainability that motivate our research are membrane-based water desalination and carbon dioxide capture. Polymer membranes for batteries, water, or carbon dioxide capture must be mechanically strong with selective transport properties. Nanostructured polymeric materials can exhibit such combination of properties.

We are interested in the dynamics of these heterogeneous polymer materials, such as block copolymers and polymer-grafted nanoparticles. Multiple phases dispersed throughout a material enables advanced properties that cannot be achieved in materials without structure. For example, we can combine a hydrophilic phase that conducts water or ions with a hydrophobic material that provides mechanical strength. The effect of structure on water and ion transport as well as mechanical strength can be complex. Therefore, we pursue advanced experimental techniques that allow us to measure multicomponent diffusion and local relaxations. Please visit our research page for more details.

  • Congratulations Dr. Kim!

      Kyoungmin Kim successfully defended his dissertation on July 1st. Congratulations Dr. Kim! He is now working as a Research Scientists at Storagenergy Technologies

  • Undergraduate Researcher Presented IDEA Grant Results

      The President's Showcase of Undergraduate Research Excellence hosted undergraduate researchers presenting their IDEA Grant results. Ashley David, a member of the Hallinan Lab, was awarded the Steve Madden Undergraduate Research Award. She presented the results of her research on Analyzing the Soret Effect Using Time- Resolved FTIR-ATR. Her participation was made possible by this award. Her efforts have resulted in new insight into the Soret Effect and a manuscript submitted for publication. You can view the presentation slides here here.

  • Polymer and Composite Electrolyte Review Webinar

      The Frontiers of Solid State Batteries Webinar hosted jointly by MRS and ECS includes a presentation by Prof. Daniel Hallinan (starting at 1:01:00). He reviews the article on polymer and composite electrolytes that was published with Dr. Irune Villaluenga and Prof. Nitash Balsara in the October 2018 issue of MRS Bulletin (Volume 43). The review introduces important transport parameters, needed to model battery performance. It introduces a dimensionless number, the Newman number, that is important for comparing different classes of electrolytes. It also covers ion transport in model composites, block copolymers that have well defined structure. It present simple effective-medium-theory type expressions to predict the composite transport properties based on the transport properties of each phase. The review also discusses the importance of matching transport properties of different phases. Finally, it discusses reaction kinetics in solid electrolytes.

  • Postdoctoral Opportunities

    Olympics and Science?

    • Recent and Upcoming Seminars and Conferences

      2022 ISA-institute of Advanced Studies

      17:30 - 19:00, July 12, 2022

      "Lecture on Polymers and Viscoelasticity - available on zoom"
      Speaker Daniel T. Hallinan
      Date/time Tuesday, July 12, 2022
      Location: or: Sala Rossa, Palazzo Marchesini, Via Marsala, 26 - Bologna

      2022 APS March Meeting-Chicago

      11:00AM - 2:00PM, March 16, 2022

      "Modeling Dynamic Swelling of Polymer-Based Artificial Muscles"
      Speaker Shefik D. Bowen
      Date/time Wednesday, March 16, 2022
      Location: McCormik Place Exhibit Hall F1

      2022 APS March Meeting-Chicago

      8:00AM - 10:48AM, March 18, 2022

      "Assessing Effective Medium Theories for Conduction through Lameller Grains"
      Speaker Omar Taleb
      Date/time Friday, March 18, 2022
      Location: McCormik Place W-185A


      Thermal Diffusion in Polymer Electrolyte Membranes
      Daniel T Hallinan (Florida State University), Micah Silverman (Florida State University), Kyoungmin Kim(Florida State University), Jesufane (Jenny) Mentor (Nextera Energy)

      In most mixtures, a concentration gradient develops in response to a temperature gradient. Steady state is quantified by the Soret coefficient, which is the ratio of the thermal diffusion coefficient to the mutual diffusion coefficient. Polymer electrolytes are an interesting class of materials to study in this regard because they could potentially be used in thermogalvanic cells to convert temperature gradients to electricity. Soret coefficients were measured in thermogalvanic cells with lithium electrodes and a dry polymer electrolyte composed of poly(ethylene oxide) (PEO) and lithium bis‐trifluoromethanesulfonylimide (LiTFSI). Voltage and power were measured in response to temperature gradients. Voltage was used to calculate the concentration gradient (and thereby Soret coefficient). Interestingly, the magnitude of Soret coefficient was similar to that in small‐molecule electrolytes and significantly less than that in neutral polymer blends. Surprisingly, the Soret coefficient of this polymer electrolyte depends on salt concentration. In order to understand the concentration dependence, separate measurements of mutual and thermal diffusion of LiTFSI in PEO-based polymers was conducted with time-resolved infrared spectroscopy. *Supported by the National Science Foundation (NSF) and Florida State University (FSU). *NSF Award

      12:27 PM to 12:39 PM Modeling Dynamic Swelling of Polymer-Based Artificial Muscles
      Authors: Shefik D Bowen (Florida State University), Daniel T Hallinan (Florida State University)
      Polymer-based artificial muscles could potentially replace traditional motors and actuators in applications where weight and flexibility are important, such as soft robotics, active prosthetics, and microfluidics. Material chemistry and muscle geometry are important parameters that impact device performance, e.g. strain, strain rate, lifetime, achievable work, and efficiency. Modeling the rate and degree of swelling of polymer fibers is an essential part of developing materials and designing muscles that perform as desired. This study is motivated by the possibility of significant actuation from twisted and coiled polymer fibers that rely on radial swelling to produce reversible work. An analytical thermodynamic expression (based on Flory-Huggins Theory) was combined with a numerical transport model in order to simulate transient swelling of a polymeric network driven by diffusion and migration. The numerical model evaluates the impact of polymer swelling on transport in polymers directly by locally accounting for the length increase of discrete elements due to solvent presence, which cannot be done analytically. The combined model of transient radial swelling of polymer fibers can be used for parametric studies or analysis of experimental data. This study will aid efforts to identify the best material candidates for practical use as artificial muscle fibers and will help evaluate the geometry needed to achieve device requirements.
      This tudy is supported by *NSF Award Abstract # 1735968CREST Center for Complex Materials Design for Multidimensional Additive Processing (CoManD).

    • Graduate Research Seminars

      11 AM, Fridays

      FAMU-FSU College of Engineering, A113
      or AME Center, Room 106 (see schedule)