Prof. Timothy M Swager

John D MacArthur Professor of Chemistry
Director, Deshpande Center for Technological Innovation

Primary DLC

Department of Chemistry

MIT Room: 18-597

Assistant

Emily Wensberg
wensberg@mit.edu

Areas of Interest and Expertise

Supramolecular and Materials Chemistry, with an Emphasis on the Synthesis and Contructions of Functional Assemblies
Chemical Sensors
Design, Synthesis, and Investigation of Novel Polymers and Receptors
Applications in Environmental Monitoring and Medicine
Liquid Crystals
Chemosensors
Metallo-Receptors
Organic Chemistry
Inorganic Chemistry
Physical Chemistry
Synthesis and Characterization of Electronically and Optically Active Polymers and Polymer Sensory Materials
Signal Amplification in Conducting Polymers
Colorants
Nanoscience
Solar Energy
Complex Emulsions
Active Packaging; Moisture/Oxygen
Explosives (Developing in 2 Phases; Only Become Explosive in the Mixing Phase and, Finding Substitutes)

Research Summary

Broadly focused on synthetic, supramolecular, analytical, and materials chemistry, the Swager Group is interested in a spectrum of topics with an emphasis on the synthesis and construction of functional assemblies.

Swager's group research is broadly focused on synthetic, supramolecular, analytical, and materials chemistry. We are interested in a spectrum of topics with an emphasis on the synthesis and construction of functional assemblies. Molecular recognition pervades a great deal of research. Chemosensors require recognition elements to discriminate chemical signals. Electronic polymers are one of the areas that our group is well known for having made many innovations. We are constantly developing new electronic structures, properties, and uses for these materials. Recently we have launched an effort to create functionalized carbon nanotubes and graphenes. We have advanced new chemical methods for their functionalization and utilization in electrocatalysis and chemical and radiation sensing. In the area of liquid crystals we make use of molecular complimentarity and receptor-ligand interactions to provide novel organizations.

Student and postdoctoral researchers in my group are exposed to a broad range of topics including synthetic chemistry, organic chemistry, polymer chemistry, inorganic chemistry, organometallic chemistry, electro-chemistry, photo-chemistry, and liquid crystal science. The subject areas are briefly summarized here and more can be learned by visiting my group’s home page.

(1) Chemosensors are molecule-based devices that are designed and synthesized to detect a specific chemical signal. Chemosensory research is directed at harnessing the unique properties of conjugated organic polymers (molecular wires). We demonstrated some years ago that “wiring molecular recognition sites in series” leads to ultra-high sensitivity and that this approach has universal applicability for the amplification of chemosensory responses. The principles developed by our group can amplify chemosensory signals by many orders of magnitude. Sensor principles are now broadly practiced by many research groups around the world and are the basis of a number or emerging sensor technologies. Nonetheless, there are still many basic scientific principles to be determined. Continuing work is focused upon the design, synthesis, and investigation of novel electronic polymers, graphenes, carbon nanotubes, and receptors.

(2) We are developing new classes of Metal Containing Conductive Polymers and Nano-Carbon Composites that contain transition metal centers, for catalytic and recognition functions. Our group has succeeded in making the most conductive transition metal hybrid structures and has demonstrated that these materials have important new transport characteristics and properties. We have also used covalent assemblies of carbon nanotubes and transition metals to give materials with high electrochemical catalytic activity.

(3) Liquid crystals are undergoing a scientific renaissance! New liquid crystalline phases are being frequently discovered and supramolecular science is making extensive use of liquid crystals as a method for self-assembly. Interests are broad and include the design and discovery of new classes of liquid crystals, investigations of liquid crystals with high chirality, demonstrations of novel electro-optical effects, development of molecular recognition approaches to liquid crystals, and investigations of new types of polymer/liquid crystal composites. One very useful method for the discovery of novel phases is to assemble liquid crystals from molecules with unusual shapes. Efforts are focused on transition metal complexes, highly unsaturated organic compounds, and polymers that offer special optical, electronic, and structural properties.

(4) The ability to organize molecules into complex supramolecular structures is a critical foundation for the development of future molecular device technologies. We are applying molecular recognition principles to the formation of new polymers architectures and organizations.

(5) Dynamic nuclear polarization is a method that can provide orders of magnitude enhancements in NMR. In collaboration with Professor Griffin (MIT Chemistry) we have developed biradical systems that allow for efficient spin polarization transfer from electrons to nuclei. Compounds provide record-level enhancements and are being used widely by the NMR community. Ongoing efforts are to create ever more efficient biradicals for the hyperpolarization of nuclei and to extend these methods to MRI imaging.

(6) Synthesis underpins all aspects of our program and over the years we have developed new reaction methodologies. Areas of specific interest are methods to create polycyclic aromatic systems, novel chain growth polymerizations to create polyaromatic structures, directed annulations, complex block copolymers, and novel methodology for the functionalization of nanocarbon materials.

Recent Work

  • Video

    Timothy Swager-2.5.2021

    February 5, 2021Conference Video Duration: 30:51
    Timothy Swager
    John D. MacArthur Professor of Chemistry

    9.29.20-Nano-Sense-Day-3-Intro-Panel-1

    September 29, 2020Conference Video Duration: 50:55
    Brian Anthony
    Associate Director, MIT.nano
    Faculty Lead, Industry Immersion Program in Mechanical Engineering
    Vladimir Bulovic
    Director, MIT.nano; Fariborz Maseeh (1990) Chair in Emerging Technology; Professor of Electrical Engineering, MacVicar Fellow
    Michael Cima
    David H. Koch Professor of Engineering, MIT Koch Institute for Integrative Cancer Research
    Amy Moran-Thomas
    Alfred Henry and Jean Morrison Hayes Career Development Associate Professor of Anthropology at MIT
    Timothy Swager
    John D. MacArthur Professor of Chemistry

    9.21.20-Nano.Sense-Day_1-Welcome-Sesson-1: CELL AND SUBCELL

    September 21, 2020Conference Video Duration: 127:34
    Brian Anthony
    Associate Director, MIT.nano
    Faculty Lead, Industry Immersion Program in Mechanical Engineering
    Vladimir Bulovic
    Director, MIT.nano; Fariborz Maseeh (1990) Chair in Emerging Technology; Professor of Electrical Engineering, MacVicar Fellow

    Keynote: MATERIALS, MEDICINE, HEALTH: SENSING THE WORLD AROUND US AT ALL SCALES
    Elazer Edelman
    Director, Institute for Medical Engineering and Science, MIT
    Democratizing Single Molecule Nanoarrays
    Ashwin Gopinath
    Assistant Professor, Mechanical Engineering
    Interferometric Imaging for Studying Sickle Cell Disease and Cancer Metastasis
    Peter So
    Professor, Mechanical Engineering and Biological Engineering
    Dynamic Lens Systems for Biosensing
    Timothy Swager
    John D. MacArthur Professor of Chemistry

    Timothy Swager - 2018 Japan Conference

    February 2, 2018Conference Video Duration: 44:53

    Carbon Nanotube Based Chemical Sensors

    This lecture will detail the creation of ultrasensitive sensors based on electronically active conjugated polymers (CPs) and carbon nanotubes (CNTs). Conceptually a single nano- or molecular-wire spanning between two electrodes would create an exceptional sensor if binding of a molecule of interest to it would block all electronic transport. Nanowire networks of CNTs modified chemically or in composites with polymers provide for a practical approximation to the single nanowire scheme. Creating chemiresistive and FET based sensors that have selectivity and accuracy requires the development of new methods. I will discuss covalent and non-covalent medication of CNTs with groups that impart selectivity for target analytes. This can involve reactions at the CNT sidewalls and rapping of the CNTs with CPs. Highly specific chemical processes orthogonal responses can be produced for mixtures of analytes through careful integration of chemical functionality. A prevailing problem in all chemiresistive schemes, which is seldom highlighted by researchers, is drift. This is intrinsic for systems that need to interface with their surroundings and changes in the position of ions of small changes in the organization of the CNTs relative to each other, the electrodes, or their surroundings can change the base resistance. I will detail different methods designed to lock the CNT networks in place. These novel compositions are also designed to accommodate functionality and I will demonstrate how we can use a diversity of transition metals to create selective responses to gases. We will also show that this scheme creates CNT networks that are robust enough for solution sensing and demonstrate chemiresistive based glucose sensing. I will also briefly discuss the successful use of CNT based gas sensors for the detection of ethylene and other gases relevant to agricultural and food production/storage/transportation and integrated systems that increase production, manage inventories, and minimize losses.

    Timothy Swager - RD2017

    November 22, 2017Conference Video Duration: 34:29

    Chemistry of the Graphene Surface for the Creation of Functional Nanomaterials

    The utility of carbon nanomaterials is highly dependent upon the precision upon which they can be assembled and functionalized. New methods enable high impact applications in sensing, mechanical, membrane, and energy storage/conversion. Approaches to the formation of functional assemblies of carbon nanotubes will be described that involved the non-covalent immobilization of the materials into functional assemblies. In a non-covalent method, no direct chemical bonds are made to the carbon nanotubes, thereby leaving their electronic properties intact. New covalent connections to the graphene surfaces (sidewalls) of the carbon nanotubes will also be discussed and how these materials can serve to modify their electronic properties for devices as well as hard wire functional assemblies to the carbon nanotubes to provide interactions with chemicals (sensors) or electrocatalysis (energy conversion). Many of these methods are also applicable to the functionalization of graphite to create new forms of graphene. We will also show how high purity graphene can be produced in using new scalable electrochemical methods.

    2017 MIT Research and Development Conference

    Timothy Swager - 2017 Health Conf

    September 26, 2017Conference Video Duration: 36:27

    Molecular Electronics for Chemical Sensors

    This lecture will detail the creation of ultrasensitive sensors based on electronically active conjugated polymers (CPs) and carbon nanotubes (CNTs). A central concept that a single nano- or molecular-wire spanning between two electrodes would create an exceptional sensor if binding of a molecule of interest to it would block all electronic transport. The use of molecular electronic circuits to give signal gain is not limited to electrical transport and CP-based fluorescent sensors can provide ultratrace detection of chemical vapors via amplification resulting from exciton migration. Nanowire networks of CNTs provide for a practical approximation to the single nanowire scheme. These methods include abrasion deposition and selectivity is generated by covalent and/or non-covalent binding selectors/receptors to the carbon nanotubes. Sensors for a variety of materials and cross-reactive sensor arrays will be described. The use of carbon nanotube based gas sensors for the detection of ethylene and other gases relevant to agricultural and food production/storage/transportation are being specifically targeted and can be used to create systems that increase production, manage inventories, and minimize losses.

    2017 MIT Health Sensing & Imaging Conference