Yinlong Du

Ultra low dielectric constant soluble polyhedral oligomeric silsesquioxane (POSS)–poly(aryl ether ketone) nanocomposites with excellent thermal and mechanical properties

A series of novel ultra low dielectric constant soluble organic–inorganic nanocomposites in which nanoscale octa-aminophenyl polyhedral oligomeric silsesquioxanes (octaAmino POSS-Ph8) were covalently linked onto the fluoropoly(ether ether ketone)s (PEEK-CF3-COOH) were prepared and characterized. The chemical structures of the polymer matrix and nanocomposites were confirmed by 1H NMR and FT-IR spectra. The analysis of wide-angle X-ray diffraction (WAXD) and X-ray photoelectron spectra (XPS) indicated that the POSS clusters were successfully incorporated into the polymer matrix and the homogeneous dispersion of POSS cages in the polymer matrix was evidenced by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) (Si-mapping). Furthermore, the influence of the incorporation of POSS particles on the properties of nanocomposites is investigated. The dielectric constants of the organic–inorganic nanocomposites were drastically reduced relative to neat PEEK-CF3-COOH films and the dielectric constant could achieve as low as 1.71 (1 MHz). Besides, the thermal and mechanical properties of the nanocomposites were significantly improved by incorporation of octaAmino POSS-Ph8 moieties. Meanwhile, the nanocomposite thin films still retained the good transparency.

High-contrast electrochromic and electrofluorescent dual-switching materials based on 2-diphenylamine-(9,9-diphenylfluorene)-functionalized semi-aromatic polymers

Two kinds of electrochromic and photoluminescence-active semi-aromatic polyamide and polyimide were prepared via condensation polymerization from a novel diamine, N,N-di-(4-aminophenyl)-2-amino-9,9-diphenylfluorene, with cycloaliphatic dicarboxylic acid and dianhydride, respectively. These polymers showed excellent solubility and increased thermal stability with 10% weight loss in excess of 450 °C in a N2 atmosphere. Due to the stable electrochemistry and improved solid-state fluorescence properties, the polymer films exhibited repeatable and high-contrast electroswitching in both coloration and emission (ΔT% = 80–85%, Ioff/Ion = 152.1–177.9). Especially, the polyamide still showed excellent electroswitching stability even after hundreds of cycles.

A novel poly(ethylene glycol)–grafted poly(arylene ether ketone) blend micro-porous polymer electrolyte for solid-state electric double layer capacitors formed by incorporating a chitosan-based LiClO4 gel electrolyte

A novel strategy was used to prepare a high performance micro-porous polymer electrolyte (MPE) from a poly(arylene ether ketone) (PAEK)/poly(ethylene glycol) grafted poly(arylene ether ketone) (PAEK-g-PEG) polymer composite membrane matrix incorporating a chitosan based LiClO4 gel electrolyte. The morphology, porosity, and thermal and mechanical properties of the PAEK/PAEK-g-PEG polymer blend membrane matrix were investigated. To improve the liquid retention capacity of the MPE, a simple but effective method involving the addition of chitosan was implemented. The effects of chitosan concentration on the liquid uptake and leakage behaviors as well as the ionic conductivity of the electrolyte were also evaluated. The synthesized MPE exhibited an ionic conductivity as high as 8 × 10−3 S cm−1 at room temperature. More importantly, a novel solid-state electric double layer capacitor (S-EDLC) could be fabricated using the synthesized MPE and activated carbon electrodes. For comparison, an EDLC was also assembled using the corresponding aqueous electrolyte and a commercial separator (NKK-MPF30AC-100). Alternating current (AC) impedance measurement results showed that the interfacial compatibility of the MPE and the activated carbon electrodes was high. Meanwhile, the as-prepared S-EDLC showed a specific capacitance of 118.63 F g−1, with an energy density of 7.87 W h kg−1 and power density being 95.97 W kg−1 at a current density of 1 A g−1. Furthermore, the S-EDLC exhibited greater cell-cycling stability after 5000 charge/discharge cycles than did the EDLC, indicating that this novel MPE should be suitable for use in EDLCs and other energy storage systems.

Poly(arylene ether ketone)s with pendant porphyrins: synthesis and investigation on optical limiting properties

This paper describes the synthesis and characterization of a novel series of poly(arylene ether ketone)s bearing porphyrin pendants, along with the demonstration of their nonlinear optical and optical limiting properties at 532 nm in both THF and films. The incorporation of pendant porphyrins was done through a modified esterification using a copoly(arylene ether ketone) with free carboxyl groups and mono-hydroxyphenyl porphyrins with different substituents and center metal. The introduction of porphyrin in the polymer was confirmed by IR, 1H NMR, UV-vis, fluorescence spectroscopies, and WAXD. Investigation of thermal properties indicated that the poly(arylene ether ketone)s with porphyrin pendants possessed higher Tgs, and slightly lower decomposition temperatures than the starting copolymers. The results of optical limiting and Z-scan measurements demonstrated that the porphyrinated poly(arylene ether ketone)s exhibited strong optical limiting responses and nonlinear absorption properties with the nonlinear absorption coefficient β in the order of 10−9 (m W−1) magnitude. The effects of pendant porphyrin structure on the thermal, mechanical, linear and nonlinear optical properties of the poly(arylene ether ketone)s were investigated in detail.

A flexible solid-state supercapacitor based on a poly(aryl ether ketone)–poly(ethylene glycol) copolymer solid polymer electrolyte for high temperature applications

In order to meet the requirement of high temperature applications, a high thermal stability solid polymer electrolyte is prepared with a poly(aryl ether ketone)–poly(ethylene glycol) copolymer (i.e., PAEK–PEG) as a polymer host, and LiClO4 as an electrolyte salt. A novel flexible solid-state supercapacitor is then assembled by the resultant solid polymer electrolyte and activated carbon electrodes. The electrochemical properties of the supercapacitor are analyzed over a wide temperature range of 30–120 °C. The fabricated supercapacitor has excellent electrochemical performance especially at high temperature (e.g. high specific capacitance of 103.17 F g−1 at 0.1 A g−1 and an energy density of 6.76 W h kg−1 with a power density of 9.55 W kg−1 at 120 °C). Simultaneously, this solid polymer electrolyte based supercapacitor possesses excellent flexible bending properties and outstanding cycle stability of negligible specific capacitance loss after 2000 cycles at various temperatures, demonstrating its feasibility as an energy device for high temperature applications.

Porphyrin–poly(arylene ether sulfone) covalently functionalized multi-walled carbon nanotubes: synthesis and enhanced broadband nonlinear optical properties

A novel multi-walled carbon nanotube (MWNT) hybrid was synthesized by covalently attaching a porphyrinated poly(arylene ether sulfone) onto the surface of carbon nanotubes. The polymer functionalized nanotube exhibited excellent solubility in organic solvents, and the weight% of MWNTs in the resulting hybrid was found to be 36%. Considerable fluorescence quenching and shortened fluorescence lifetime were observed in the MWNT hybrid due to the photo-induced electron/energy transfer behavior from porphyrin moieties to MWNTs. Z-scan measurements demonstrated the improved broadband nonlinear optical performance of the MWNT hybrid at both 532 and 1064 nm in nanoseconds, which is attributed to the accumulation effect of nonlinear absorption and scattering, and a remarkable photo-induced electron/energy transfer process. Meanwhile, the MWNT hybrid can be homogeneously dispersed in a polymer matrix, further fabricated into a uniform film with high transparency and ultrafast optical limiting response under femtosecond laser pulses.

Synthesis and optical properties of hyperbranched PAEKs containing porphyrin and its metal derivatives

Novel functional hyperbranched poly(aryl ether ketone)s (HPAEKs) bonded with nonlinear optical chromophores (meso-tetrakis(4-hydroxyphenyl) porphyrin, THPP and its metal derivatives) were synthesized and characterized by 1H-NMR and UV-Vis absorption spectra. The incorporation of chromophores into HPAEKs endowed HPAEKs novel NLO and OL properties. Indeed, dendritic architecture allowed for maximum dispersion of the chromophores, avoided aggregation, more optical limiting property was obtained. Simultaneously, they retained the excellent properties of the materials, particularly in thermal stability. Their optical properties were evaluated by nonlinear optical analyses and optical limiting. The results showed that these polymers possessed good optical limiting (OL) property and large nonlinear optical (NLO) susceptibilities (ca. 10−12 esu). All polymers containing chromophores presented excellent thermal stability (DT5 > 524.17 °C).

Design and preparation of silica tube/poly(aryl ether ketone) composites with low dielectric constant

Silica tubes with uniform size were designed and prepared by hydrolyzing tetraethyl orthosilicate using D,L-tartaric acid as the self-assembly template. And a novel series of silica tube/poly(aryl ether ketone) composite films were prepared in which silica tubes were covalently bonding onto the side chains of poly(aryl ether ketone) (PAEK-COOH) in the presence of silane coupling agent (γ-aminopropyltriethoxysilane, KH-550). The morphology of the silica tubes was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The chemical structures of the polymer matrix and composites were confirmed by 1H NMR and FT-IR spectra. The patterns of wide-angle X-ray diffraction (WAXD) and X-ray photoelectron spectra (XPS) indicated that the silica tubes were incorporated into the PAEK successfully and the homogeneous dispersion of silica tubes in PAEK was illustrated by scanning electron microscopy (SEM). Furthermore, the impact of silica tubes on the properties of composites was investigated in detail. The composite films exhibited low dielectric constants ranging from 2.22 to 2.57 at 1 MHz owing to the introduction of silica tubes, which was found to be distinctly lower than that of the pristine PAEK-COOH film. Meanwhile, these composites still retained excellent thermal and mechanical properties.

Poly(arylene ether)s based on platinum(II) acetylide complexes: synthesis and photophysical and nonlinear absorption properties

The design and fabrication of nonlinear absorption molecule-embedding solid-state optical power limiting materials are significant but challenging. In the present study, we first report on the synthesis and optical properties of two poly(arylene ether)s incorporating platinum acetylide in the backbones, as well as the fabrication of solid-state optical power limiting materials based on the prepared polymers. The concentrations of platinum acetylide chromophores in the polymer chains were examined to be 19 wt% and 26 wt%, which are the highest levels for non-metal polyyne polymers. Poly(arylene ether)s with platinum acetylide exhibited good mechanical strength, thermal stability, and high glass transition temperature. Investigation of their photophysical behavior revealed that at a high linear transmittance, the polymers showed longer triplet state lifetimes and larger nonlinear absorption coefficients than the corresponding platinum acetylide monomers as a result of the shielding effect. Solid-state monoliths based on platinum acetylide-incorporating poly(arylene ether)s exhibited excellent reverse saturable absorption and optical limiting performance at 532 nm, compared to the optically opaque platinum acetylide chromophore doped polymer monoliths that are formed by severe aggregation.

High performance disulfonated poly(arylene ether sulfone)/poly(ethylene oxide) composite membrane used as a novel separator for supercapacitor with neutral electrolyte and activated carbon electrodes

High performance disulfonated poly(arylene ether sulfone)/poly(ethylene oxide) (SPAES/PEO) composite membranes were prepared by a simple method such as a novel separator saturated by the lithium sulfate (Li2SO4) aqueous electrolyte for application in supercapacitors (SCs). As prepared composite membranes exhibit excellent mechanical properties and thermal stabilities, which are beneficial for the safety in potential applications, meanwhile, the addition of PEO on membrane also enhanced the affinity with electrolyte and the ion conduction for lithium salts. In addition, the SC cell was fabricated with optimized SPAES/PEO composite membrane and activated carbon electrodes with Li2SO4 aqueous electrolyte. The obtained SC with the SPAES/PEO separator revealed a specific capacitance of 142.5 F g−1 at a current density of 0.1 A g−1. Furthermore, the energy density of the SC was promoted to 19.04 Wh kg−1 due to the wide working voltage range of the neutral electrolyte, and the SC exhibited an excellent coulombic efficiency of almost 99% and nearly 100% cycling retention after 5000 galvanostatic charge/discharge cycles. All of these results indicated that SPAES/PEO composite membrane is suitable as a novel separator for SC.