Polyurethanes prepared from isocyanates containing triphenylamine derivatives: synthesis and optical, electrochemical, electrochromic and memory properties

Abstract

Electrochromic behaviors of PU (M1)-b thin film (in CH 3 CN with 0.1 M LiCO 4 as the supporting electrolyte) at 0.0 V to 1.40 V (insets are the pictures of oxidized PU (M1)-b). Abstract Two novel series of triphenylamine (TPA)-containing aromatic polyurethanes (PUs) were synthesized via polymerization of N', N'-bis (α-naphthyl)-N, N'-bis (4-phenylisocyanate) biphenyl (M1) and N, N'-diphenyl-N, N'-bis (4-phenylisocyanate) biphenyl (M2) with different dihydroxy compounds. The structures of the polymers were characterized by Fourier Transform Infrared(FT-IR) spectroscopy, hydrogen nuclear magnetic resonance ( 1 H-NMR) and carbon nuclear magnetic resonance ( 13 C-NMR); and the thermostability and morphology were studied by 2 thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The molecular weights were measured to be from 1.02 × 10 4 to 1.31 × 10 4 by gel permeation chromatography (GPC). The polymers were coated onto indium tin oxide (ITO) and the electrochromic properties were investigated by using the ultraviolet visible (UV-vis) absorption spectra and cyclic voltammetry (CV). The energy gaps were in the range of 2.21-2.26 eV. The polymer films revealed good stability of the electrochromic characteristics by continuous cyclic scans, with a color changing from neutral yellowish to a blue doped form at applied potentials. Meanwhile, PUs film exhibited non-volatile write-once-read-many-times (WORM) memory behavior in the device resulting from the non-isolated donor-acceptor (D-A).

Radiation Crosslinking of Polyurethanes: Characterization by FTIR, TGA, SEM, XRD, and Raman Spectroscopy

“…The polyurethane was only turned to yellow after being irradiated in absence of oxygen under vacuum conditions, while those exposed to UV radiation (365 nm) exhibited strong UV absorption and gave purple color that increased with gamma radiation doses increased from 0 up to 150 kGy ( Figure 6 curve II(a )-(d )) illustrating the purple color of solid PU films. It can be explained by the - * transitions resulting from charge transfer between nitrogen atoms from PU units and the bisphenol rings with the electron-donating of methyl (-CH 3 ) substituent in the bisphenol of PU [33]. This indicated that the irradiated PUs have conjugated structure and are capable of emitting fluorescence light.…”

Transition Metal-Ions Incorporated PEG300 and TDI Based Hydroxy-Terminated Polyurethanes

“…The strong band observed at 1658 cm -1 may be attributed to >C=O stretching vibration of urethane [37], while the bands at 1533 cm -1 may be assigned to N-H out of plane bending in urethane [38], while the band at 1043 cm -1 may be corroborated to C-O-C stretching vibration. [39] The spectral data of M(II)-HTPU 300 [where, M = Mn(II) d 5 , Co (II) d 7 , Ni(II) d 8 and Zn(II) d 10 ] can be extensively discussed. The peak centered between 3277-3300 cm -1 may be ascribed to -NH stretching vibration while the strong peak appearing between 1696-1712 cm -1 may be assigned to >C=O stretching vibration of urethane groups.…”

“…Schiff bases [5], porphyrins, N-heheterocycles [6], polyureas [7], and polyurethanes (PUs) [8]. The chemical and structural properties of PUs can easily be modulated to generate tailored polymers with predetermined features [9].…”

Novel organosoluble polyarylates based on diphenylamine-fluorene units

“…21 It is well known that TPA-containing polymer could be used as electrochromic materials due to the obvious color changes in the oxidization process from TPA to TPA þ , and compared with the other materials, the electrochromic TPA derivatives are usually colorless in the neutral states which is very beneficial for the applications in smart window. [22][23][24][25] However, the cation radical of TPA is not stable, which could easily form tetraphenylbenzidine through tail-to-tail coupling reaction. 26,27 To solve this problem, the introduction of electro-donating groups in the para-phenyl position of TPA could reduce the oxidation potential and thus increase the stability of the electrochemical redox.…”