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Research

Conductive Polymer/Carbon Nanotube Composites

Carbon nanotubes (CNTs) have attracted enormous interest due to their remarkable mechanical, thermal, and electrical properties. The CNTs applications include nanoelectronics, sensors, energy storage devices, photovoltaics, and nanocomposite materials. One of the key challenges to fully realize their extensive applications is the dispersion and functionalization of carbon nanotubes. We have developed a simple and versatile approach to disperse CNTs within various solvents and polymer matrices using conjugated block copolymers with tunable functionalities. In contrast to invasive chemical functionalization of CNTs, this approach provides non-invasive method to disperse and functionalize CNTs. With a simple sonication, the conjugated polymer blocks, such as polythiophenes, can form strong π-π interactions with carbon nanotube walls, while the non-conjugated polymer blocks will provide the de-bundled CNTs with good solubility and stability in a wide range of organic solvents and host polymer matrices. The non-conjugated polymer blocks can also introduce a variety of functionalities to CNTs, allowing further functionalization such as depositing nanoparticles on CNT surfaces. Additionally, we have fabricated ordered poly(3-hexylthiophene)(P3HT) supramolecular structures on CNTs through a CNT enhanced crystallization process. Such bottom-up strategy provides a general approach to build functional conductive supramolecular structures that will lead to numerous applications in nanoscale electronics. Our current work aims at fabricating multifunctional CNT or graphene/conductive block copolymer composites and exploring their applications in energy conversion and storage devices.

Polymer Derived Ceramics

Ceramics have been extensive used and investigated due to their intriguing properties including high thermal and chemical stability, piezoresistivity, and optoelectrical properties. Unlike conventional ceramics obtained by sintering corresponding powders, the polymer-derived ceramics (PDCs) are synthesized by direct thermal decomposition of polymeric precursors. Such technology allows the control of ceramic composition through the functionalization of polymer precursors. Our research focuses on fabricating functional ceramics by incorporating various materials in polymers, and studying their electrical and mechanic properties. We have developed a unique simple technique to synthesize Si-C-N(O)-Al ceramic with high piezoresistivity from aluminum doped polysilazanes. Ceramic fibers were also fabricated via the electrospinning and PDCs techniques. Preceramic polymer (polysilazane) fibers were fabricated via electrospinning. The obtained polymer fibers were then pyrolyzed into Si-C-N(O)-Al ceramic fibers at 1000 oC in Ar. Based on our discovery of dispersing CNT using conductive block copolymers, we have successfully incorporated CNTs in polymer derived ceramics, which leads to improved electrical conductivity and mechanical properties. Si-C-N(O)-Al ceramics possess excellent thermal stability, low thermal conductivity, piezoresistivity, and resistance to oxidation/corrosion. We are studying their potential applications in high temperature catalyst supports, sensors and protecting materials.

Surface Functionalization of Microfluidic Systems

The development of micropumps and microvalves has made it possible to realize a fully integrated microfluidic system for biochemical analysis. Nano/microliter fluid handling on lab-on-a-chip (LOC) by passive fluidic manipulation often employs a hydrophobic surface as a valve in the microchannel network and an external pneumatic control coupled with capillary action to discretely manipulate the fluids. We have extended the surface functionalization via the layer-by-layer deposition of polyelectrolytes and nanoparticles to microfluidic systems, and have fabricated a fully integrated microfluidic valve with a switchable, thermosensitive polymer surface through the combination of the layer-by-layer self-assembly technique and microfabrication. We also developed an analytical model for the switching characteristic of a thermosensitive surface that is very useful for the characterization and design purpose. Current research is focusing on generating cell patterns in microfluidic systems for biomedical application.

Ultra-light Multi-walled Carbon Nanotube Aerogel

Ultra-light multi-walled carbon nanotube (MWCNT) aerogel with a density of 4 mg/cm3 was fabricated. The fabrication procedure relied on modifying MWCNTs with reactive polymer of poly (3-(trimethoxysilyl) propyl methacrylate) (PTMSPMA), whose hydrolysis and condensation introduces strong chemical bonding interaction between MWCNTs and dramatically decreases the critical gelation concentration of MWCNTs. The MWCNT aerogel has an anisotropic macroporous honeycomb structure with straight and parallel channels separated by thin MWCNT walls. The MWCNT aerogel demonstrates excellent compression recovery properties and its surface area and conductivity were characterized to be 580 m2/g and 0.67 S• cm-1, respectively. The excellent compression recovery property, high surface area, and high conductivity of the MWCNT aerogel lead to interesting pressure and chemical vapor responsive capability.

Bottom-up Assembly of Poly(3-hexylthiophene) on Carbon Nanotubes: 2D Building Blocks for Nanoscale Circuits

Hierarchical poly(3-hexylthiophene)(P3HT)/carbon nanotube (CNT) supramolecular structures were fabricated through a bottom-up CNT induced P3HT crystallization strategy. P3HT nanowires growing perpendicular from CNT surface have uniform width and height. The density and the length of these nanowires can be controlled by tuning the P3HT/CNT mass ratio. The quasi-isothermal crystallization process monitored by in-situ UV-Vis spectroscopy indicates that CNTs can greatly enhance the P3HT crystallization, and the P3HT nanowire formation follows first-order kinetics. Such bottom-up strategy provides a general approach to build 2D functional conductive supramolecular structures that will lead to numerous applications in nanoscale electronics.

Conductive block copolymer systems to disperse and stabilize CNTs

The conjugated polymer block such as polythiophenes can form strong π-π interactions with carbon nanotube walls, while the non-conjugated polymer block offers good solubility and stability in a wide range of organic solvents and host polymer matrices.

Selected Publications

  1. Didier, C. M.; Fox, D.; Pollard, K. J.; Baksh, A.; Lyer, N. R.; Bosak, A.; Sip, Y. Y. L.; Orrico, J. F.; Kundu, A.; Ashton, R. S.; Zhai, L.; Moore, M. J.; Rajaraman, S. “Fully Integrated 3D Microelectrode Arrays with Polydopamine-Mediated Silicon Dioxide Insulation for Electrophysiological Interrogation of a Novel 3D Human, Neural Microphysiological Construct” ACS Appl. Mater. Interfaces, 2023, 15, 31.
  2. Cencillo-Abad, P.; Mastranzo-Ortega, P.; Appavoo, D.; Guo, T.; Zhai, L.; Sanchez-Mondragon, J.; Chanda, D. “Reusable Structural Colored Nanostructure for Powerless Temperature and Humidity Sensing” Adv. Opt. Mat. 2023, 5, 2300300.
  3. Nierenberg, D.; Flores, O.; Fox, D. W.; Sip, Y. Y. L.; Finn, C. M; Ghozlan, H.; Cox, A.; Coathup, M.; McKinstry, K. K.; Zhai, L.; Khaled, A. R “Macromolecules Absorbed from Influenza Infection-Based Sera Modulate the Cellular Uptake of Polymeric Nanoparticles” Biomimetics, 2022, 7, 219.
  4. Fox, D. W.; Antony, D.-X.; Sip, Y. Y. L.; Fnu, J.; Rahmani, A.; Zhai, L. “Electrospun Hydrogel Fibers Guide HKUST-1 Assembly” Materials Today Communication 2022, 33, 104535.
  5. Walters, L. J.; Graig, C. A.; Dark, E.; Wayles, J.; Encomio, V.; Coldren, G.; Sailor-Tynes, T.; Fox, D. W.; Zhai, L. “Quantifying Spatial and Temporal Trends of Microplastic Pollution in Surface Water and in the Eastern Oyster Crassostrea Virginica for a Dynamic Florida Estuary” Environments, 2022, 9, 131.
  6. Burnstine-Townley, A.; Afrin, S.; Sip, Y. Y. L.; Fox, D. W.; Zhai, L. “In Situ Formation of Nanoparticles on Carbon Nanofiber Surface Using Ceramic Intercalating Agents” Journal of Composites Science, 2022, 6, 303.
  7. Stoll, S.; Hwang, J. –H.; Fox, D. W.; Kim, K.; Zhai, L. Lee, W. H. “Cost-Effective Screen-Printed Carbon Electrode Biosensors For Rapid Detection of Microcystin-LR in Surface Waters for Early Warning of Harmful Algal Blooms” Environmental Science and Pollution Research, 2022, 1.
  8. Fahad, S.; Zhang, Z.; Zhai, L.; Kushima, A. “A Liquid‐Metal Electrocatalyst as a Self‐Healing Anchor to Suppress Polysulfide Shuttling in Lithium‐Sulfur Batteries” Batteries & Supercaps, 2022, 6, e202100395.
  9. Shar, A.; Aboutalebianaraki, N.; Misiti, K.; Sip, Y. Y. L.; Zhai, L.; Razavi, M. “A Novel Ultrasound-Mediated Nanodroplet-Based Gene Delivery System for Osteoporosis Treatment” Nanomedicine: Nanotechnology, Biology and Medicine, 2022, 41, 102530.
  10. Azim, N.; Orrico, J. F. Appavoo, D.; Zhai, L.; Rajaraman, S. “Polydopamine Surface Functionalization of 3D Printed Resin Material for Enhanced Polystyrene Adhesion towards Insulation Layers for 3D Microelectrode Arrays (3D MEAs)” RSC Advances, 2022, 12, 25605.
  11. Craig, C. A.; Fox, D. W.; Zhai, L.; Walter, L. J. “In-situ Microplastic Egestion Efficiency of the Eastern Oyster Crassostrea Virginica” Marine Pollution Bulletin, 2022, 173, 113653.
  12. Fahad, S.; Zhang, Z.; Zhai, L.; Kushima, A. “A Liquid-Metal Electrocatalyst as a Self-Healing Anchor to Suppress Polysulfide Shuttling in Lithium-Sulfur Batteries” Batteries & Supercaps, 2022, e202100395.
  13. Hwang, J.-H.; Sip, Y. Y. L.; Kim, K. T.; Hang, G.; Rodriguez, K. L.; Fox, D. W.; Afrin, S,; Burnstine-Townley, A.; Zhai, L.; Lee, W. H. “Nanoparticle-embedded Hydrogel Synthesized Electrodes for Electrochemical Oxidation of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS)” Chemosphere, 2022, 296, 134001.
  14. Olimattel, K.; Zhai, L.; Sadmani, A. H. M. A. “Enhanced Removal of Perfluorooctane Sulfonic Acid and Perfluorooctanoic Acid via Polyelectrolyte Functionalized Ultrafiltration Membrane: Effects of Membrane Modification and Water Matrix” Journal of Hazardous Materials Letters, 2021, 2, 100043.
  15. Hwang, J.-H.; Fox, D.; Stanberry, J.; Anagnostopoulos, V.; Zhai, L.; Lee, W. H. “Direct Mercury Detection in Landfill Leachate Using a Novel AuNP-Biopolymer Carbon Screen –Printed Electrode Sensor” Micromachines, 2021, 12, 649.
  16. Saran, R.; Fox, D.; Zhai, L.; Chanda, D. “Organic Non-Wettable Superhydrophobic Fullerite Films” Adv. Mater. 2021, 2102108.
  17. Sip, Y. Y. L.; Fox, D.; Shultz, L.; Davy, M.; Chung, H.-S.; Antony, D.-X.; Jung, Y.; Jurca, T.; Zhai, L. “Cu-Ag Alloy Nanoparticles in Hydrogel Nanofibers for the Catalytic Reduction of Organic Compounds” ACS App. Nano Mat., 2021, 4, 6045.
  18. Fox, D. W.; Schropp, A. A; Joseph, T; Azim, N.; Sip, Y.Y. L.; Zhai, L. “Uniform Deposition of Silver Nanowires and Graphene Oxide by Superhydrophilicity for Transparent Conductive Films” ACS App. Nano Mat., 2021, 4, 7628.
  19. Esfahania, A. R.; Zhai, L.; Sadmani, A. A. H. M. “Removing Heavy Metals from Landfill Leachate using Electrospun Polyelectrolyte Fiber Mat-Laminated Ultrafiltration Membrane” Journal of Environmental Chemical Engineering, 2021, 9, 105355.
  20. Zhang, Z.; Calderon, J.; Fahad, S.; Ju, L.; Antony, D.-X.; Yang, Y.; Kushima, A.; Zhai , L. “Polymer-Derived Ceramic Nanoparticle/Edge-Functionalized Graphene Oxide Composites for Lithium-Ion Storage” ACS Appl. Mater. Interfaces, 2021, 13, 9794.
  21. Nierenberg, D.; Flores, O.; Fox, D.; Li Sip, Y. Y.; Finn, C.; Ghozlan, H.; Cox, A.; McKinstry, K.; Zhai, L.; Khaled, A. “Polymeric Nanoparticles with a Sera-Derived Coating for Efficient Cancer Cell Uptake and Killing” ACS Omega, 2021, 6, 5591.
  22. Tian, H.; Li, Z.; Feng, G.; Yang, Z.; Fox, D.; Wang, M.; Zhou, H.; Zhai, L.; Kushima, A.; Du, Y.; Feng, Z.; Shan, X.; Yang, Y. “Stable, High-performance, Dendrite-free, Seawater-based Aqueous Batteries” Nature Comm,. 2021, 12, 237.
  23. Barrios, E.; Zhai, L. “A Review of the Evolution of the Nanostructure of SiCN and SiOC Polymer Derived Ceramics and the Impact on Mechanical Properties” Molecular Systems Design & Engineering, 2020, 5, 1606-1641
  24. Olimattel, K.; Church, J.; Lee, W. H.; Chumbimuni-Torres, K.; Zhai, L.; Sadmani, A. H. M. “Enhanced Fouling Resistance and Antimicrobial Property of Ultrafiltration Membranes via Polyelectrolyte-Assisted Silver Phosphate Nanoparticle Immobilization” Membranes, 2020, 10, 293.
  25. Cherusseri, J.; Pandey, D.; Sambath, K. K.; Thomas, J.; Zhai, L. “Flexible Supercapacitor Electrodes Using Metal-Organic Frameworks” Nanoscale, 2020, 12, 17649.
  26. Appavoo, D.; Park, S. Y.; Zhai, L. “Responsive Polymers for Medical Diagnostics” J. Mater. Chem. B, 2020, 8, 6217.
  27. Carlin, J.; Graig, C.; Little, S.; Donnelly, M.; Fox, D.; Zhai, L.; Walters, L. “Microplastic Accumulation in the Gastrointestinal Tracts in Birds of Prey in Central Florida, USA” Environmental Pollution, 2020, 264,114633.
  28. Esfahania, A. R., Zhang, Z.; Sip, Y. Y. L.; Zhai, L.; Sadmani, A. A. H. M. “Removal of Heavy Metals from Water Using Electrospun Polyelectrolyte Complex Fiber Mats” Journal of Water Process Engineering, 2020, 37, 101438.
  29. Afrin, S.; Fox, D.; Zhai, L. “Organic Superhydrophobic Coatings with Mechanical and Chemical Robustness” MRS Commnications, 2020, 10, 346.
  30. Catarata, R.; Azim, N.; Bhattacharya; S.; Zhai, L. “Controlled Drug Release from Polyelectrolyte-Drug Conjugate Nanoparticles” J. Mater. Chem. B, 2020, 8, 2887.
  31. Zhai, L.; Narkar, A.; Ahn, K. “Self-Healing Polymers with Nanomaterials and Nanostructures” Nano Today, 2020, 30, 100826.

Patents

  1. Zhai, L.; Malhotra, A. “Dust and Moisture Resistant Coating Compositions, Methods and Related Coated Articles” US 10,316,217 (2019)
  2. Zhai, L.; Zou. J. “Method of Forming Carbon Nanotube or Graphene-Based Aerogels” US 9,963,570 B2 (2018)
  3. Haynie, D. T.; Zhai, L. “Polypeptide Electrospun Nanofibrils of Defined Composition” US9,869,038 B2 (2018)
  4. Haynie, D. T.; Zhai, L. “Polypeptide Electrospun Nanofibrils of Defined Composition” US 9,428,849 B2, (2016)
  5. Zhai, L.; Zou, J.; “Carbon Nanotube or Graphene-Based Aerogels” US 08,975,326 (2015)
  6. Huo, Q.; Khondaker, S.; Zou, J.; Zhai, L.; Chen, H.; Muthuraman, H. “Polymer Composites Having Highly Dispersed Carbon Nanotubes” US 08,709,292 (2014)
  7. Zhai, L.; Liu, J.; Zou, J.; Chunder, A. “Method of Forming Composite Materials including Conjugated Materials Attached to Carbon Nanotubes or Graphene” US 08,790,610 B2 (2014)
  8. Zhai, L.; Liu, J.; Zou, J.; Chunder, A. “Supramolecular Structures Comprising at Least Partially Conjugated Polymers Attached to Carbon Nanotubes or Graphenes” US 08,613,898 (2011)
  9. Zou, J.; Zhai, L.; Huo, Q. “Dispersions of Carbon Nanotubes in Copolymer Solutions and Functional Composite Materials and Coatings Therefrom” US 08,211,969 (2009)
  10. Huo, Q.; Khondaker, S.; Zou, J.; Zhai, L.; Chen, H.; Muthuraman, H. “Polymer Composites Having Highly Dispersed Carbon Nanotubes and Methods for Forming Same” US 07,951,850 (2009)
  11. Sheng, X.; Zhai, L.; Rubner, M. F.; Cohen, R. E. “Patterned Coatings Having Extreme Wetting Properties and Methods of Making” US 08,153,233 (2007)

Current Funding

  • NASA: Nanoporous lubricant-impregnated surfaces (LIS) PI:Zhai

Past Funding

  • NSF CAREER: Regioregular Poly(3-alkylthiphene) Supramolecular Structures PI: Zhai, 6/2008-5/2013
  • NSF FRG: Electronic Properties of Polymer-Derived Amorphous Ceramics Co-PI: Zhai, 9/2007-8/2010
  • NSF NUE: Preparing Undergraduates for Careers in Nanotechnology Co-PI: Zhai, 6/2008-5/2010
  • US Army Research Laboratory: Development of Surface Modification Techniques for Synthesis of Hybrid Tungsten Nano-Powders Co-PI: Zhai, 8/2006 – 8/2009
  • NSF NER: Nanoscale Optical and Electronic Processes in Active Nanostructures and Devices for Solar Energy Conversion Co-PI: Zhai, 6/2006 – 12/2007
  • Mechanical, Materials & Aerospace Engineering SFTI Ph1: Failure Mechanisms, Life Prediction and Enhanced Performance of Thermal and Environmental Barrier Coatings Co-PI: Zhai, 12/2006 – 3/2008

Graduate Students

The graduate students will be part of a new group, situated in a brand new laboratory, pursuing exciting projects in an interdisciplinary field of chemistry, physics, biology and nanoscience. They will receive a highly interdisciplinary education covering topics ranging from polymer synthesis to device physics. The future success of many emerging technologies currently under development in this country clearly depends on an expanded work force of such diverse scientists.