Solid-state carbon-13 NMR characterization of polyanilines

Kaplan, S.; Conwell, E. M.; Richter, A.F.; MacDiarmid, A. G.

doi:10.1021/ja00231a011

Cited by 109 publications

(100 citation statements)

References 5 publications

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“…Broad resonances centered at around 124.1, 142.1, and 158.2 ppm are observed. The assignment of all different carbons, presented in Table I, consistent with a benzoid-quinoid alternating structure, are those noted by Kaplan et al 34 and Hjertberg et al…”

Section: Resultssupporting

confidence: 76%

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Morphology of Segmented Polyether Based Poly(urea-urethane) Thermoplastic Elastomers

Liu

Hsu

Wang

2006

Polym J

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ABSTRACT:New aniline-containing segmented poly(urea-urethane) (PUU-OPA) based on polyether polyurethane prepolymer and an oligomer of amine-terminated polyaniline (OPA) were prepared as a conductive material. The amine-terminated functional groups of OPA were introduced into the poly(urea-urethane) (PUU) structure as a chain extender to form the hard segment of the copolymer with urea-linkage. The morphology of PUU-OPA was examined by the transmission electron microscopy (TEM) and solid-state 13 C NMR approaches. The conductivity of the copolymers is found to be ranged from 0.83 S/cm for the neat OPA to 1:96 Â 10 À6 S/cm for the resultant copolymers. TEM measurements clearly reveal the microphase separation. Various contact time CP experiments indicate that T CH and T 1 (H) of the soft segment carbons declined as the OPA content increased. These results indicate that the chain mobility and the domain size of the soft segment in the copolymer on the nanophase scale gradually decreased as the OPA content increased. [doi:10.1295/polymj.PJ2005204] KEY WORDS 13 C NMR / TEM / Poly(urea-urethane) / Morphology / Polyurethane / Polyaniline (PANI), one of the most promising intrinsically conducting polymers, has been attracted considerable attention in recent years because it has a relatively high conductivity and potential application in electronic devices.1,2 Polyaniline is generally prepared by oxidative the polymerization of aniline in acid media using an external oxidant such as ammonium peroxydisulfate, (NH 4 ) 2 S 2 O 8 , and can exist as a number of unique structures, characterized by the oxidation state, which determines the ratio of amine to imine nitrogens, and the extent of protonation. 3 The emeraldine base (EB) is one of the several possible structures. The conducting form of polyaniline can be easily prepared by doping the EB with a protonic acid resulting in a complex acid salt. The members of the polyaniline family are difficult to handle because of their brittleness and poor solubility in polar organic solvents. The processing of emeraldine base is difficult, because EB decomposes below its softening or melting temperature.4-7 Therefore, the processibility of EB has been the subject of several investigations over the last few years. [8][9][10][11] The earlier attempts at processing polyaniline focused on modifying the chain structure by copolymerization or derivation with hydrophilic or alkyl groups. These attempts resulted in a first successful step toward the so-called soluble polymer. Recently, attempts have been made to synthesize aniline oligomers with well-defined structures and amine end-groups and thus improve their solubility and capacity to undergo further polymerization have been reported.12-18 Polyurethanes (PU), comprising a polyether or polyester soft (flexible) segment and a diisocyanate-based hard (rigid) segment, are well known to be tough materials and are typically employed as additives to improve the toughness of brittle materials. The incompatibility between the hard segment and the ...

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Section: Resultssupporting

confidence: 76%

“…34 Figure 1b presents the 13 C CP/MAS NMR spectrum of OPA. Broad resonances centered at around 124.1, 142.1, and 158.2 ppm are observed.…”

Section: Resultsmentioning

confidence: 99%

Morphology of Segmented Polyether Based Poly(urea-urethane) Thermoplastic Elastomers

Liu

Hsu

Wang

2006

Polym J

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“…Covalent functionalisation was also verified using cross-polarization magic angle spinning solidstate nuclear magnetic resonance (SSNMR). The spectrum obtained for unmodified PAni is consistent with spectra in the literature [22], and predominant Results obtained by thermal gravimetric analysis (TGA) are also consistent with nanofibre functionalisation. These reveal that PAni, PAni-C 10 COOH and PAni-NH 2 have different decomposition profiles (Figure 2).…”

Section: Preparation and Characterisation Of Functionalised Pani Nanosupporting

confidence: 88%

Polyaniline nanofibres as templates for the covalent immobilisation of biomolecules

et al. 2011

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The attachment of antibodies onto polyaniline nanofibres using covalent chemistry was investigated for the first time. Polyaniline nanofibres were functionalised post-polymerisation to attach either amide or carboxylic acid side-groups. These templates could then be further modified to attach antibodies, specifically in this instance mouse immunoglobulin G (IgG). The resultant conjugates were characterised using a variety of techniques including infrared, UVvisible and Raman spectroscopy. Conjugates were then used to detect secondary antibodies (anti-

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“…The emeraldine form of polyaniline shows the highest electrical conductivity after it had been doped with protonic acid [8]. Neutral, non-redox organic compounds, such as chloroform or toluene, are able to change the conductance of doped polyaniline films through swelling effects [9].…”

Section: Polyemeraldine (Fig 1: Top) Consists Of Amine (-Nh-) and Immentioning

confidence: 99%

Doped and dedoped polyaniline nanofiber based conductometric hydrogen gas sensors

Sadek

Włodarski

Kalantar‐zadeh

et al. 2007

Sensors and Actuators A: Physical

141

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Template-free, rapid polymerisation was employed to synthesize polyaniline nanofibers using chemical oxidative polymerisation of aniline, with HCl as a dopant. The doped and dedoped nanofibers were deposited onto conductometric sapphire transducers for gas sensing applications. The sensors were exposed to various concentrations of hydrogen (H 2 ) gas at room temperature. The sensitivity was measured to be 1.11 for doped and 1.07 for dedoped polyaniline nanofiber sensors upon exposure to 1% H 2 . Fast response times of 28 seconds and 32 seconds were observed for dedoped and doped sensors respectively. The dedoped nanofiber sensor outperforms the doped sensor in terms of baseline stability and repeatability. Due to its room temperature operation, the gas sensor is promising for environmental applications.

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Solid-state carbon-13 NMR characterization of polyanilines

Cited by 109 publications

References 5 publications

Morphology of Segmented Polyether Based Poly(urea-urethane) Thermoplastic Elastomers

Morphology of Segmented Polyether Based Poly(urea-urethane) Thermoplastic Elastomers

Polyaniline nanofibres as templates for the covalent immobilisation of biomolecules

Doped and dedoped polyaniline nanofiber based conductometric hydrogen gas sensors

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