Co-reporter:Aaron F. Baldwin, Tran Doan Huan, Rui Ma, Arun Mannodi-Kanakkithodi, Mattewos Tefferi, Nathan Katz, Yang Cao, Rampi Ramprasad, and Gregory A. Sotzing
Macromolecules 2015 Volume 48(Issue 8) pp:2422-2428
Publication Date(Web):April 15, 2015
DOI:10.1021/ma502424r
Large dielectric constant and band gap are essential for insulating materials used in applications such as capacitors, transistors and photovoltaics. Of the most common polymers utilized for these applications, polyvinyldiene fluoride (PVDF) offers a good balance between dielectric constant, >10, and band gap, 6 eV, but suffers from being a ferroelectric material. Herein, we investigate a series of aliphatic organotin polymers, p[DMT(CH2)n], to increase the dipolar and ionic part of the dielectric constant while maintaining a large band gap. We model these polymers by performing first-principles calculations based on density functional theory (DFT), to predict their structures, electronic and total dielectric constants and energy band gaps. The modeling and experimental values show strong correlation, in which the polymers exhibit both high dielectric constant, ≥5.3, and large band gap, ≥4.7 eV with one polymer displaying a dielectric constant of 6.6 and band gap of 6.7 eV. From our work, we can identify the ideal amount of tin loading within a polymer chain to optimize the material for specific applications. We also suggest that the recently developed modeling methods based on DFT are efficient in studying and designing new generations of polymeric dielectric materials.
Co-reporter:Amrita Kumar, Michael T. Otley, Fahad Alhasmi Alamar, Yumin Zhu, Blaise G. Arden and Gregory A. Sotzing
Journal of Materials Chemistry A 2014 vol. 2(Issue 14) pp:2510-2516
Publication Date(Web):10 Jan 2014
DOI:10.1039/C3TC32319F
The establishment of a relationship between device performance parameters such as switch speed and photopic contrast with device composition, electrochromic polymer thickness, and gel electrolyte composition is reported here for a versatile one-step preparation method of relatively large area, 105 cm2, solid-state electrochromic devices. The electrochromic polymer, hereby, generated from a monomer after device construction, i.e. in situ, is a way to simplify the fabrication of electrochromic devices by reducing waste generation and assembly time as well as by increasing the versatility of device manufacturing in an open atmosphere. Photopic contrast is a critical property for electrochromic displays, windows, and lenses necessitating the study of how changing the selected material and device properties such as monomer diffusion, thickness of the electrochromic polymer layer, and ionic conductivity of the electrolyte impact electrochromic device functionality. More specifically photopic contrast performance is evaluated as a function of polymerization time, effective electrochromic polymer layer thickness, monomer loading, salt loading, thickness of the gel electrolyte, and in situ conversion temperature. Photopic contrasts of 47% for polybiphenylmethyloxymethyl-3,4-propylenedioxythiophene (BPMOM-ProDOT), 46% for poly2,2-dimethyl-3,4-propylenedioxythiophene (PProDOT-Me2), and 40% for poly(3,4-ethylenedioxythiophene) (PEDOT) without background correction were achieved.
Co-reporter:Michael T. Otley, Fahad Alhashmi Alamer, Yumin Zhu, Ashwin Singhaviranon, Xiaozheng Zhang, Mengfang Li, Amrita Kumar, and Gregory A. Sotzing
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 3) pp:1734
Publication Date(Web):January 17, 2014
DOI:10.1021/am404686w
We utilized our in situ method for the one-step assembly of single-layer electrochromic devices (ECDs) with a 3,4-propylenedioxythiophene (ProDOT) acrylate derivative, and long-term stability was achieved. By coupling the electroactive monomer to the cross-linkable polymer matrix, preparation of the electrochromic ProDOT polymer can occur followed by UV cross-linking. Thus, we achieve immobilization of the unreacted monomer, which prevents any degradative processes from occurring at the counter electrode. This approach eliminated spot formation in the device and increased stability to over 10 000 cycles when compared to 500 cycles with conventional ProDOT devices wherein the monomer is not immobilized. The acrylated electrochromic polymer exhibits similar electrochromic properties as conventional ProDOT devices, such as photopic contrast (48% compared to 46%) and switch speed (both 2 s). This method can be applied to any one-layer electrochromic system where improved stability is desired.Keywords: conjugated polymer; displays; electrochromic; electrochromic devices; electropolymerization; windows;
Co-reporter:Donna Marie D. Mamangun, Jose L. Santana, Fahima Ouchen, James G. Grote and Gregory A. Sotzing
RSC Advances 2014 vol. 4(Issue 94) pp:52155-52155
Publication Date(Web):20 Oct 2014
DOI:10.1039/C4RA90032D
Correction for ‘Orthogonal alignment of DNA using hexafluoroisopropanol as solvent for film castings’ by Donna Marie D. Mamangun et al., RSC Adv., 2014, 4, 39798–39801.
Co-reporter:Fahad Alhashmi Alamer;Michael T. Otley;Yujie Ding
Advanced Materials 2013 Volume 25( Issue 43) pp:6256-6260
Publication Date(Web):
DOI:10.1002/adma.201302729
Co-reporter:Aaron F. Baldwin;Rui Ma;Chenchen Wang;Rampi Ramprasad
Journal of Applied Polymer Science 2013 Volume 130( Issue 2) pp:1276-1280
Publication Date(Web):
DOI:10.1002/app.39240
Most polyolefins that are used for dielectric materials exhibit a low dielectric constant and operating temperatures up to 70°C. Polyimides offer a means to a higher dielectric constant material by the introduction of a polar group in the polymer backbone and are thermally stable at temperatures exceeding 250°C. A common dianhydride, pyromellitic dianhydride (PMDA), is reacted with various short-chain diamines to produce polymers with high imide density. Homopolymers and copolymers synthesized had dielectric constants ranging from 3.96 to 6.57. These materials exhibit a dielectric constant twice that of biaxially oriented polypropylene and therefore a twofold increase in capacitance as well as maintaining low dissipation factors that are acceptable for this application. The experimental dielectric constants of these materials are also compared to density functional theory calculations and exhibit a close relationship. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1276-1280, 2013
Co-reporter:Mustafa S. Yavuz, Gregory A. Sotzing
European Polymer Journal 2012 Volume 48(Issue 4) pp:875-880
Publication Date(Web):April 2012
DOI:10.1016/j.eurpolymj.2012.01.013
Herein we demonstrated the preparation of 3,4-ethylenedioxythiophene (EDOT) containing polynorbornylene brushes on Au surfaces via surface-initiated ring-opening metathesis polymerization (SI-ROMP). Using solid-state oxidative crosslinking technique, these polymer brushes were electrochemically converted to conjugated polymer networks. Grazing-angle FTIR spectra of polymer brushes clearly showed the characteristic vibrations of EDOT and norbornylene groups. Furthermore, densely covered Au substrates with polynorbornylene brushes were characterized by using scanning electron microscopy and atomic force microscopy.Graphical abstractPolynorbornylene brushes containing 3,4-ethylenedioxythiophene (EDOT) pendant moieties on gold surfaces were prepared via surface-initiated ring opening metathesis polymerization (SI-ROMP). Tethered EDOT and norbornylene groups on a Au surface were clearly identified from grazing-angle FTIR spectra. These polymer brushes were electrochemically converted to conjugated polymer networks using solid-state oxidative crosslinking technique. Furthermore, the polynorbornylene brushes densely covered the gold substrates which were microscopically characterized by SEM and AFM.Highlights► Preparation of EDOT containing polynorbornylene brushes on gold surfaces. ► Surface-initiated ring-opening metathesis polymerization (SI-ROMP) on Au surface. ► Conjugated polymer networks using solid-state oxidative crosslinking technique. ► Grazing-angle FTIR characterization of polymer brushes.
Co-reporter:Yujie Ding, Michael A. Invernale, Donna M. D. Mamangun, Amrita Kumar and Gregory A. Sotzing
Journal of Materials Chemistry A 2011 vol. 21(Issue 32) pp:11873-11878
Publication Date(Web):07 Jul 2011
DOI:10.1039/C1JM11141H
Herein we present a simple and elegant method for the creation of solid-state conjugated polymer devices. Their electrochromic properties were fully explored in this study, but one could envision the extension of this method to displays, solar cells, OLEDs, transistors, or many other applications. We prepared conductive polymer composites or blends within a polymer electrolyte using electrochemical polymerization of these monomers inside an assembled solid-state device. This method will work for any monomer that can be dissolved in the gel electrolyte. This technique offers simplicity in device construction, is easily adapted to patterned systems and comprises a low-waste assembly process. Our novel approach of assembling polymer electrochromic devices avoids the tedious cleaning process of the substrates, produces almost no waste, and by inkjetting insulating materials to mask the substrates, letters and high-resolution images could be achieved inside the converted polymer devices. Electrochromic devices utilizing PEDOT assembled by our method showed compatible switching speed and durability with a slightly higher contrast ratio.
Co-reporter:Daminda Navarathne, Yogesh Ner, James G. Grote and Gregory A. Sotzing
Chemical Communications 2011 vol. 47(Issue 44) pp:12125-12127
Publication Date(Web):14 Oct 2011
DOI:10.1039/C1CC14416B
An efficient cascade FRET was realized in solid state DNA-CTMA thin films using a three chromophore system without any covalent attachments. The extent of energy transfer from Cm102 to SRh was studied and found to improve eight-fold using the bridging dye Pm567.
Co-reporter:Daminda Navarathne, Yogesh Ner, Menka Jain, James G. Grote, Gregory A. Sotzing
Materials Letters 2011 Volume 65(Issue 2) pp:219-221
Publication Date(Web):31 January 2011
DOI:10.1016/j.matlet.2010.09.033
DNA–magnetite hybrid nanofibers were fabricated by electrospinning a spin dope consisting of oleic acid coated magnetite nanoparticles and DNA–CTMA in ethanol/chloroform mixed solvent. The fabricated nanofibers exhibit superparamagnetic behaviour owing to embedded magnetite nanoparticles. It is demonstrated that these nanofibers can be used as effective detoxification materials in aqueous media as a combined result of DNA's affinity to both organic and inorganic toxicants, high surface area of the nanofibers and the fast and easy separation due to magnetite nanoparticles under external magnetic field. In addition to detoxification, these novel hybrid nanofibers have potential applications in many technological areas such as catalysis and drug delivery.
Co-reporter:Michael A. Invernale;Yujie Ding;Donna Marie D. Mamangun;Mustafa S. Yavuz
Advanced Materials 2010 Volume 22( Issue 12) pp:1379-1382
Publication Date(Web):
DOI:10.1002/adma.200902975
Co-reporter:Michael A. Invernale, Yujie Ding and Gregory A. Sotzing
ACS Applied Materials & Interfaces 2010 Volume 2(Issue 1) pp:296
Publication Date(Web):January 4, 2010
DOI:10.1021/am900767p
Herein we describe the preparation and characterization of reflective-type electrochromic devices using stretchable, conductive fabric electrodes. Two fabrics were used in this study: woven stainless steel mesh and Lycra spandex impregnated with a conducting polymer (poly[3,4-ethylenedioxythiophene]-poly[styrene sulfonate], PEDOT-PSS). Electrochromic polymers were prepared on the surface of these fabric electrodes and devices were assembled. The time taken for the electrochromic polymer to switch between colored states in devices prepared with stainless steel electrodes (conductivity ca. 9,800 S/cm) was ca. 0.3 s, whereas that using PEDOT-PSS loaded Lycra (conductivity ca. 0.1 S/cm) was a few seconds. The iris effect was evaluated for each of the device architectures, showing no effect for steel mesh/steel mesh devices and a propagating front for spandex-based devices. The electrochromic spandex functioned in solution while being stretched. In addition, stenciled devices were built. Such fabric electrochromic devices represent a critical step toward the realization of totally chameleonic fabric.Keywords: electrochromic devices; electrochromic devices; functional textile; organic electronics; spandex/fabric
Co-reporter:Yujie Ding, Michael A. Invernale and Gregory A. Sotzing
ACS Applied Materials & Interfaces 2010 Volume 2(Issue 6) pp:1588
Publication Date(Web):May 18, 2010
DOI:10.1021/am100036n
A stretchable e-textile was fabricated by simply soaking Spandex fabric in a conductive polymer aqueous dispersion, PEDOT-PSS. The resulting conductive fabric had an average conductivity of 0.1 S/cm. Subjecting the fabric to more than one soaking step increased the conductivity of the fabric up to ca. 2.0 S/cm resulting in a 33% faster switching speed. This simple methodology is not limited to Spandex (50% nylon/50% polyurethane). Several other fabric compositions were investigated for their conductivity via this process, including 100% cotton, 60% cotton/40% polyester, 95% cotton/5% Lycra, 60%polyester/40% rayon, 100% polyester, and 80% nylon/20% Spandex, listed in order of decreasing hydrophilicity. Those fabrics with higher water uptake resulted in higher conductivities upon soaking in PEDOT-PSS. Electrochromic polymers coated on the fabric could be switched between their different colored states, even upon stretching of the Spandex. SEM revealed that the electrochromic polymer coated on the substrate separated under stretching, uncovering the color of the base conducting fabric. It was found that the PEDOT-PSS was not a film on the Spandex but rather homogenously dispersed nanoparticles within the fabric matrix forming a percolated network.Keywords: conductive polymer; conductive textile; electrochromic; PEDOT-PSS; stretchable electrode
Co-reporter:Yogesh Ner, Michael A. Invernale, James G Grote, Jeffrey A. Stuart, Gregory A. Sotzing
Synthetic Metals 2010 Volume 160(5–6) pp:351-353
Publication Date(Web):March 2010
DOI:10.1016/j.synthmet.2009.11.003
Herein we report the template polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) using a biomacromolecule, DNA, as the polyelectrolyte. The resultant bio-composite material formed a stable, aqueous-dispersible system. Higher conductivities than that of conventionally prepared PEDOT-PSS without conductivity enhancing additives were observed (ca. 1.0 S/cm versus ca. 0.15 S/cm). The material was redox active in the dispersed state and in the solid state. The DNA double helix was found to undergo changes in conformation upon redox switching, resulting in controllable variance of its ability to polarize light. This non-acidic template is non-corrosive and is therefore an ideal candidate for use in device applications. The system described is potentially bioactive and biocompatible, as well, which would further extend its applicability.The preparation of a water-dispersible conducting polymer system comprised of a DNA-PEDOT bio-composite using DNA as a polyelectrolyte template for polymer growth is described. Optoelectronic properties, conductivity, and morphology are explored in this potentially bioactive and biocompatible system.Neutral and oxidized state of a solution of DNA-PEDOT in water.
Co-reporter:Tanmoy Dey, Daminda Navarathne, Michael A. Invernale, Ian D. Berghorn, Gregory A. Sotzing
Tetrahedron Letters 2010 Volume 51(Issue 16) pp:2089-2091
Publication Date(Web):21 April 2010
DOI:10.1016/j.tetlet.2010.02.036
We describe a new route for the synthesis of thieno[3,4-b]thiophene, alkyl derivatives thereof, seleno[3,4-b]thiophene, and thieno[3,4-b]furan made from inexpensive starting materials, such as thiophene-2-carboxylic acid and furan-2-carboxylic acid. Such fused heterocycles are of great interest for low band gap organic semiconductors and applications including OLEDs, organic photovoltaic cells, and electrochromics.Structures of the fused heterocycles prepared herein.
Co-reporter:Bongkoch Somboonsub, Suttisak Srisuwan, Michael A. Invernale, Supakanok Thongyai, Piyasan Praserthdam, Daniel A. Scola, Gregory A. Sotzing
Polymer 2010 Volume 51(Issue 20) pp:4472-4476
Publication Date(Web):17 September 2010
DOI:10.1016/j.polymer.2010.08.008
We showed that it is possible to use sulfonated poly(amic acid)s (SPAA) to template polymerize 3,4-ethylenedioxythiophene (EDOT) to PEDOT, resulting in an aqueous dispersion of conducting polymer. This study compares PEDOT with poly(aniline) (PANi) and poly(pyrrole) PPy using the same and another, more rigid, poly(amic acid) template. A variety of system parameters, including reaction time, conductivity, and overall thermal stability, were noted to change systematically depending on the systems chosen. PANi-SPAA takes less than one tenth of the reaction time of PEDOT-SPAA (12 h versus 7 days), and results in higher conductivities at room temperature (ca. 10 S/cm). However, it is not as thermally stable as the PEDOT-SPAA system; conductivity is not measureable after annealing at 300 °C. PPy-SPAA was found to be more thermally stable than PANi-SPAA (less mass lost at 300 °C), but it was still more conductive than un-doped PEDOT-SPAA by a factor of 1000 (ca. 1.0 S/cm).
Co-reporter:Bongkoch Somboonsub, Michael A. Invernale, Supakanok Thongyai, Piyasan Praserthdam, Daniel A. Scola, Gregory A. Sotzing
Polymer 2010 Volume 51(Issue 6) pp:1231-1236
Publication Date(Web):11 March 2010
DOI:10.1016/j.polymer.2010.01.048
We describe the template polymerization of EDOT with sulfonated poly(amic acid) (SPAA), resulting in a stable conducting polymer aqueous dispersion, PEDOT-SPAA, with particle size ca. 63 nm. In films of PEDOT-SPAA, the sulfonated poly(amic acid) template undergoes imidization within 10 min at temperatures greater than 150 °C, resulting in PEDOT-sulfonated poly(imide) (PEDOT-SPI) with 10-fold conductivity enhancement. This material is highly thermally stable as compared to PEDOT-PSS. Thermal stability is necessary for many processing applications of conducting polymers, including annealing for OPVs and melt-processing of polycarbonate for device encasement. Isothermal TGA experiments were run at 300 °C for PEDOT-PSS and PEDOT-SPAA and we found that PEDOT-SPAA had a smaller slope for degradation. Annealing of films at 300 °C for 10 min caused the conductivity of PEDOT-PSS films to be unmeasurable (<1 × 10−5 S/cm), while those of PEDOT-SPAA increased 6-fold. Secondary doping of the PEDOT-SPAA system with additives commonly used for PEDOT-PSS was also investigated.
Co-reporter:Michael A. Invernale;Samuel A. Pendergraph;Mustafa S. Yavuz;Matthew Ombaba
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 9) pp:2024-2031
Publication Date(Web):
DOI:10.1002/pola.23972
Abstract
Processability remains a fundamental issue for the implementation of conducting polymer (CP) technology. A simple synthetic route toward processable precursors to CPs (main chain and side chain) was developed using commercially available materials. These soluble precursor systems were converted to conjugated polymers electrochemically in aqueous media, offering a cheaper and greener method of processing. Oxidative conversion in aqueous and organic media each produced equivalent electrochromics. The precursor method enhances the yield of the electrochromic polymer obtained over that of electrodeposition, and it relies on a less corruptible electrolyte bath. However, electrochemical conversion of the precursor polymers often relies on organic salts and solvents. The ability to achieve oxidative conversion in brine offers a less costly and a more environmentally friendly processing step. It is also beneficial for biological applications. The electrochromics obtained herein were evaluated for electronic, spectral, and morphological properties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2024–2031, 2010
Co-reporter:Michael A. Invernale, Jayesh G. Bokria, Matthew Ombaba, Ki-Ryong Lee, Donna M.D. Mamangun, Gregory A. Sotzing
Polymer 2010 Volume 51(Issue 2) pp:378-382
Publication Date(Web):21 January 2010
DOI:10.1016/j.polymer.2009.12.015
We have developed two approaches to processable precursors to conjugated polymers: main-chain and side-chain. Upon oxidative conversion to the conjugated polymer, a main-chain precursor yielded a nearly perfect spectral match, an identical λmax, and an equivalent band gap to that of electrodeposited chromophore, resulting in a color match. This precursor method has the potential to incorporate any chromophore and achieve spectral and color matching with relative ease, as opposed to extensive synthetic monomer design. We describe the synthesis and characterization of a new side-chain and two new main-chain precursor polymers, each of which contains a derivative of 3,4-propylenedioxythiophene, ProDOT-Me2. The side-chain precursor tethers one ProDOT-Me2 molecule to a poly(norbornene) backbone; the main-chain systems are perfectly alternating copolymers of ProDOT-Me2, one with dimethylsilane and one with tetramethyldisiloxane. Electronic and optical properties for these converted precursors were described and compared to electrodeposited PProDOT-Me2.
Co-reporter:Michael A. Invernale, Venkataramanan Seshadri, Donna Marie D. Mamangun, Yujie Ding, James Filloramo and Gregory A Sotzing
Chemistry of Materials 2009 Volume 21(Issue 14) pp:3332
Publication Date(Web):May 22, 2009
DOI:10.1021/cm900843b
Ion storage layers have been employed in the construction of electrochromic devices to enhance device lifetimes through balanced ion shuttling. This has led to a search for a material which has a high charge capacity as well as optical transparency. Poly(thieno[3,4-b]thiophene) (PT34bT) exhibits high transparency in the visible region in both its neutral and oxidized states, in addition to having a high charge capacity, making it an ideal candidate for an ion storage layer. Herein we report devices fabricated by electrodeposition of several common chromophores, such as PEDOT, PDiBz-ProDOT, and PProDOT-Me2. Devices were made with and without a balanced layer of PT34bT on the counter electrode and were probed for coloration and contrast. It was found that the addition of the ion storage layer did not alter the color of any of the devices and resulted in a minimal, predicted loss of contrast corresponding to the thickness of the ion storage layer.
Co-reporter:Yogesh Ner, Chris Asemota, James R. Olson and Gregory A. Sotzing
ACS Applied Materials & Interfaces 2009 Volume 1(Issue 10) pp:2093
Publication Date(Web):September 22, 2009
DOI:10.1021/am900382f
A simplified approach to constructing a composite material comprised of aligned electrospun nanofibers onto a flexible substrate consisting of a microfilament yarn is presented. The metal-coated knit patterns of the microfilament yarn play the role of the parallel electrode, required for the alignment of electrospun nanofibers. Hybrid materials with knitted textile as a support material and aligned high-surface-area nanofibers could represent ideal materials for use in the filtration, optical, and biomedical industries.Keywords: electrospinning; fiber alignment; nanocomposite; PLLA
Co-reporter:Mustafa S. Yavuz, Gary C. Jensen, David P. Penaloza, Thomas A. P. Seery, Samuel A. Pendergraph, James F. Rusling and Gregory A. Sotzing
Langmuir 2009 Volume 25(Issue 22) pp:13120-13124
Publication Date(Web):October 19, 2009
DOI:10.1021/la901779k
We have achieved reversible tunability of local surface plasmon resonance in conjugated polymer functionalized gold nanoparticles. This property was facilitated by the preparation of 3,4-ethylenedioxythiophene (EDOT) containing polynorbornene brushes on gold nanoparticles via surface-initiated ring-opening metathesis polymerization. Reversible tuning of the surface plasmon band was achieved by electrochemically switching the EDOT polymer between its reduced and oxidized states.
Co-reporter:Yogesh Ner;JamesG. Grote Dr.;JeffreyA. Stuart Dr.;GregoryA. Sotzing
Angewandte Chemie 2009 Volume 121( Issue 28) pp:5236-5240
Publication Date(Web):
DOI:10.1002/ange.200900885
Co-reporter:Yogesh Ner, Jeffrey A. Stuart, Gregg Whited, Gregory A. Sotzing
Polymer 2009 50(24) pp: 5828-5836
Publication Date(Web):
DOI:10.1016/j.polymer.2009.09.017
Co-reporter:Yogesh Ner;JamesG. Grote Dr.;JeffreyA. Stuart Dr.;GregoryA. Sotzing
Angewandte Chemie International Edition 2009 Volume 48( Issue 28) pp:5134-5138
Publication Date(Web):
DOI:10.1002/anie.200900885
Co-reporter:Jayesh G. Bokria;Arvind Kumar;Venkataramanan Seshadri;Arlene Tran
Advanced Materials 2008 Volume 20( Issue 6) pp:1175-1178
Publication Date(Web):
DOI:10.1002/adma.200602023
Co-reporter:Yanbing Wang, Gregory A. Sotzing and R. A. Weiss
Chemistry of Materials 2008 Volume 20(Issue 7) pp:2574
Publication Date(Web):March 13, 2008
DOI:10.1021/cm800005r
Conductive composite foams were prepared by exposing iodine-loaded polyurethane (PU) foams to pyrrole vapor. The kinetics, equilibrium, and mechanism of the in situ polymerization of pyrrole by iodine within a PU foam was investigated. The dopant for the polypyrrole (PPy) was primarily I3−, which formed a charge-transfer complex (PPy-I2) with the amine group of the PPy. The conductivity of the composite foams increased with increasing concentration of the PPy-I2 complex and depended on the distribution of the PPy-I2 complex in the PU matrix and the concentration ratio of PPy and iodine. The chemical structure, morphology, mechanical properties, and thermal stability of the composite foams were also characterized.
Co-reporter:Yogesh Ner, James G. Grote, Jeffrey A. Stuart and Gregory A. Sotzing
Soft Matter 2008 vol. 4(Issue 7) pp:1448-1453
Publication Date(Web):01 May 2008
DOI:10.1039/B717581G
Nanoscale fibers and non-woven meshes composed of DNA complexed with a cationic surfactant (cetyltrimethylammonium chloride, or CTMA) have been fabricated through electrospinning. The DNA–CTMA complex can be electrospun far more easily than DNA alone. Incorporation of a hemicyanine chromophore resulted in materials that demonstrated amplified emission as compared to thin films of identical composition. The enhanced fluorescence resulted from both the fiber morphology (5–6-fold amplification) and specific interactions (groove-binding) between the chromophore and DNA (18–21-fold amplification). The mechanical properties of freestanding electrospun non-woven fiber meshes were evaluated, and revealed stress-induced alignment of DNA strands within the DNA–CTMA fibers. These fiber-based materials are easily processable into a variety of morphologies, and have promise for applications in molecular electronics, filtration, sensors, and the medical industry.
Co-reporter:Arvind Kumar, Jayesh G. Bokria, Zeki Buyukmumcu, Tanmoy Dey and Gregory A. Sotzing
Macromolecules 2008 Volume 41(Issue 19) pp:7098-7108
Publication Date(Web):September 17, 2008
DOI:10.1021/ma702773e
A new optically transparent, near-infrared-absorbing low energy gap conjugated polymer, poly(thieno[3,4-b]furan) (PT34bF), with promising attributes for photovoltaics is reported herein. PT34bF was prepared electrochemically, and upon redox cycling, doping was found to be anion dominant. The energy gap of the polymer was found to be 1.04 eV as calculated from the low-energy edge of the absorption spectrum of the neutral polymer at −0.6 V and 1.03 eV for the chemically neutralized polymer using hydrazine. The polymer is pale blue in the neutral form and a more transparent pale blue in the oxidized conducting state with photopic transmittances of 62% and 72% (ITO glass substrate not subtracted), indicating the possibility of application as a transparent conductor or an ion-storage layer for electronic devices. Density functional theory (DFT) calculations using B3PW91 hybrid functional have been carried out for possible connections between the three open α-positions. In addition to optimizing geometry, band structure properties such as band (energy) gaps, band widths, and effective masses were calculated for each connection. Calculations show that 4−6 connectivity is the most probable and dominant structure for the polymer resulting from T34bF, and the calculated energy gap of 1.01 eV for polymerization via this connection corresponds well with the experimentally observed value of 1.04 eV.
Co-reporter:Venkataramanan Seshadri, Javier Padilla, Humeyra Bircan, Bijan Radmard, Russell Draper, Mike Wood, Toribio F. Otero, Gregory A. Sotzing
Organic Electronics 2007 Volume 8(Issue 4) pp:367-381
Publication Date(Web):August 2007
DOI:10.1016/j.orgel.2007.01.004
Solid-state electrochromic devices, based on poly-(3,6-bis(2-(3,4-ethylenedioxy)thienyl)-N-methylcarbazole) (PBEDOT-NMCz) and poly((3,4-ethylenedioxy)thiophene) (PEDOT), having 30 cm2 active switching area, low voltage consumption, photopic contrasts of ca. 30% and switching speeds as low as 0.6 s, were prepared and studied. A special design of electrochemical cell allowed us to electrodeposit films of conducting polymer over large areas. Photopolymerization of the gel is a fast and straightforward way to assemble sealed and solid-state devices. Addition of different amounts of plastizicer to a photopolymerizable PEO-based gel electrolyte enhanced switching speed performance over approximately two orders of magnitude. Cyclic voltammetry was shown as a tool to evaluate shorcircuited devices.
Co-reporter:John G. D'Angelo;Rene Sawyer;Arvind Kumar;Amber Onorato;Christopher McCluskey;Laura Vollenweider;Rebecca French;Jay Chou;Nicholas Reyes;Suzanne Warner;Jason Stenzel;Michael B. Smith;Christopher Delude
Journal of Polymer Science Part A: Polymer Chemistry 2007 Volume 45(Issue 11) pp:2328-2333
Publication Date(Web):19 APR 2007
DOI:10.1002/pola.21973
We show that a widely used conducting polymer, poly(3,4-ethylene dioxythiophene) (PEDOT), reacts with benzylic alcohols upon heating under an inert atmosphere to give the corresponding homoether and water without the need to attach a secondary reagent or other reactive unit. This reaction does not appear to result from endogenous acid or from a buildup of acid on the polymer. Apart from the water byproduct, small amounts of aldehyde are also produced during this process. Far from being chemically inert, PEDOT facilitates facile reactions with benzylic alcohols. Because alcohols are common additives to conducting polymers, this reaction may be detrimental to the long-term stability of devices using PEDOT.
Co-reporter:S.-Y. Jang;V. Seshadri;M.-S. Khil;A. Kumar;M. Marquez;P. T. Mather;G. A. Sotzing
Advanced Materials 2005 Volume 17(Issue 18) pp:
Publication Date(Web):8 AUG 2005
DOI:10.1002/adma.200500577
Welded conducting polymer nanofibers (see Figure) with rapid electrochromic switching speeds have been prepared by electrospinning a soluble precursor polymer with pendant heterocycles into nanofibers which are subsequently crosslinked via solid-state oxidative crosslinking. The switching speeds between the oxidized and neutral states for these nanofiber mats is about twenty times faster than electrochemically prepared conducting polymer films.
Co-reporter:B. Lee;V. Seshadri;H. Palko;G. A. Sotzing
Advanced Materials 2005 Volume 17(Issue 14) pp:
Publication Date(Web):8 JUL 2005
DOI:10.1002/adma.200500210
Co-reporter:Rui Ma ; Aaron F. Baldwin ; Chenchen Wang ; Ido Offenbach ; Mukerrem Cakmak ; Rampi Ramprasad
ACS Applied Materials & Interfaces () pp:
Publication Date(Web):
DOI:10.1021/am502002v
Development of new dielectric materials is of great importance for a wide range of applications for modern electronics and electrical power systems. The state-of-the-art polymer dielectric is a biaxially oriented polypropylene (BOPP) film having a maximal energy density of 5 J/cm3 and a high breakdown field of 700 MV/m, but with a limited dielectric constant (∼2.2) and a reduced breakdown strength above 85 °C. Great effort has been put into exploring other materials to fulfill the demand of continuous miniaturization and improved functionality. In this work, a series of polyimides were investigated as potential polymer materials for this application. Polyimide with high dielectric constants of up to 7.8 that exhibits low dissipation factors (<1%) and high energy density around 15 J/cm3, which is 3 times that of BOPP, was prepared. Our syntheses were guided by high-throughput density functional theory calculations for rational design in terms of a high dielectric constant and band gap. Correlations of experimental and theoretical results through judicious variations of polyimide structures allowed for a clear demonstration of the relationship between chemical functionalities and dielectric properties.
Co-reporter:Yujie Ding, Michael A. Invernale, Donna M. D. Mamangun, Amrita Kumar and Gregory A. Sotzing
Journal of Materials Chemistry A 2011 - vol. 21(Issue 32) pp:NaN11878-11878
Publication Date(Web):2011/07/07
DOI:10.1039/C1JM11141H
Herein we present a simple and elegant method for the creation of solid-state conjugated polymer devices. Their electrochromic properties were fully explored in this study, but one could envision the extension of this method to displays, solar cells, OLEDs, transistors, or many other applications. We prepared conductive polymer composites or blends within a polymer electrolyte using electrochemical polymerization of these monomers inside an assembled solid-state device. This method will work for any monomer that can be dissolved in the gel electrolyte. This technique offers simplicity in device construction, is easily adapted to patterned systems and comprises a low-waste assembly process. Our novel approach of assembling polymer electrochromic devices avoids the tedious cleaning process of the substrates, produces almost no waste, and by inkjetting insulating materials to mask the substrates, letters and high-resolution images could be achieved inside the converted polymer devices. Electrochromic devices utilizing PEDOT assembled by our method showed compatible switching speed and durability with a slightly higher contrast ratio.
Co-reporter:Amrita Kumar, Michael T. Otley, Fahad Alhasmi Alamar, Yumin Zhu, Blaise G. Arden and Gregory A. Sotzing
Journal of Materials Chemistry A 2014 - vol. 2(Issue 14) pp:NaN2516-2516
Publication Date(Web):2014/01/10
DOI:10.1039/C3TC32319F
The establishment of a relationship between device performance parameters such as switch speed and photopic contrast with device composition, electrochromic polymer thickness, and gel electrolyte composition is reported here for a versatile one-step preparation method of relatively large area, 105 cm2, solid-state electrochromic devices. The electrochromic polymer, hereby, generated from a monomer after device construction, i.e. in situ, is a way to simplify the fabrication of electrochromic devices by reducing waste generation and assembly time as well as by increasing the versatility of device manufacturing in an open atmosphere. Photopic contrast is a critical property for electrochromic displays, windows, and lenses necessitating the study of how changing the selected material and device properties such as monomer diffusion, thickness of the electrochromic polymer layer, and ionic conductivity of the electrolyte impact electrochromic device functionality. More specifically photopic contrast performance is evaluated as a function of polymerization time, effective electrochromic polymer layer thickness, monomer loading, salt loading, thickness of the gel electrolyte, and in situ conversion temperature. Photopic contrasts of 47% for polybiphenylmethyloxymethyl-3,4-propylenedioxythiophene (BPMOM-ProDOT), 46% for poly2,2-dimethyl-3,4-propylenedioxythiophene (PProDOT-Me2), and 40% for poly(3,4-ethylenedioxythiophene) (PEDOT) without background correction were achieved.
Co-reporter:Daminda Navarathne, Yogesh Ner, James G. Grote and Gregory A. Sotzing
Chemical Communications 2011 - vol. 47(Issue 44) pp:NaN12127-12127
Publication Date(Web):2011/10/14
DOI:10.1039/C1CC14416B
An efficient cascade FRET was realized in solid state DNA-CTMA thin films using a three chromophore system without any covalent attachments. The extent of energy transfer from Cm102 to SRh was studied and found to improve eight-fold using the bridging dye Pm567.
![Poly[(1,3-dihydro-1,3-dioxo-2H-isoindole-2,5-diyl)carbonyl(1,3-dihydro-
1,3-dioxo-2H-isoindole-5,2-diyl)-1,3-propanediyl]](http://img.cochemist.com/ccimg/34200/34149-62-7.png)
![Poly[(1,3-dihydro-1,3-dioxo-2H-isoindole-2,5-diyl)carbonyl(1,3-dihydro-
1,3-dioxo-2H-isoindole-5,2-diyl)-1,3-propanediyl]](http://img.cochemist.com/ccimg/34200/34149-62-7_b.png)
![2H-Thieno[3,4-b][1,4]dioxepin-3-methanol, 3,4-dihydro-3-methyl-](/data/chemimg/123200/426263-16-3.png)
![2H-Thieno[3,4-b][1,4]dioxepin-3-methanol, 3,4-dihydro-3-methyl-](/data/chemimg/123200/426263-16-3_b.png)
![2H-Thieno[3,4-b][1,4]dioxepin, 3,4-dihydro-3,3-dimethyl-](/data/chemimg/102800/255901-50-9.png)
![2H-Thieno[3,4-b][1,4]dioxepin, 3,4-dihydro-3,3-dimethyl-](/data/chemimg/102800/255901-50-9_b.png)