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Flexible and stable organic field-effect transistors using low-temperature solution-processed polyimide gate dielectrics
摘要： Polyimide (PI) has been widely used as a gate dielectric due to its remarkable thermal stability, chemical resistance, and mechanical flexibility. However, the high processing temperature and high surface energy of PI gate dielectrics hinder the realization of flexible and reliable electronic applications with low-cost manufacturing. Here, a low-temperature solution-processed organic field-effect transistor (OFET) is successfully demonstrated using a fully imidized soluble PI gate dielectric. The low temperature processability of soluble PI gate dielectrics is confirmed by investigating the effect of annealing temperature on the dielectric properties and electrical characteristics. By blending 6,13-Bis(triisopropylsilylethynyl)pentacene with polystyrene, the reliability of OFET is considerably enhanced while maintaining high device performance. As a result, OFETs exhibit excellent flexibility and can be integrated with ultrathin parylene substrates without degrading device performance. This work presents the steps to develop flexible and reliable electronic applications with low-cost manufacturing.
关键词： organic field-effect transistors,solution-processed,polyimides,low-temperature,operational stability
更新于2025-11-14 15:19:41
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Revealing the correlation between molecular structure and dielectric properties of carbonyl‐containing polyimide dielectrics
摘要： Polymer dielectrics with outstanding heat resistance and advanced dielectric properties are of great importance for high-temperature capacitors in the applications of hostile circumstances. In this work, a series of aromatic carbonyl-containing polyimides (CPI) are prepared from the carbonyl dianhydride and different diamines. The correlation between molecular structure (i.e., different linked structure ( O , CH2 , SO2 ) in diamines, the length of repeating unit and the linked position (para-para or meta-meta), and properties is revealed in detail to obtain CPI dielectrics with excellent thermal resistance (glass transition temperature, Tg: 241~352°C), reasonably high dielectric constant (3.99~5.23), low dissipation factor (0.00307~0.00395), and admirable breakdown strength (425~552 MV/m) simultaneously. Particularly, CPI-5 with carbonyl structure in dianhydride and sulfonyl group in diamine proves to exhibit discharged energy density and charge–discharge efficiency of 6.34 J/cm3 and 92.3% at 500 MV/m, respectively. In addition, CPI-5 also displays stable dielectric properties in temperature range of ?50?200°C. ? 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47883.
关键词： dielectric properties,films,thermal properties,polyimides
更新于2025-11-14 14:48:53
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Low-dielectric-constant aromatic homopolyimide and copolyimide derived from pyromellitic dianhydride, 4,4′-oxydianiline, 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene
摘要： Low-dielectric-constant aromatics, homopolyimide and copolyimide, were introduced. Homopolyimides were prepared by pyromellitic dianhydride (PMDA) as an anhydride monomer and 4,40-oxydianiline (ODA), 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as an amine monomer. The copolyimides were prepared with PMDA as an anhydride monomer, ODA as an amine monomer with the addition of 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as another amine monomer. The polyimides were well characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, thermomechanical analysis, dielectric measurements, and tensile testing. The homopolyimide and copolyimides showed lower dielectric constants than the homopolyimide formed by ODA and PMDA. The results also indicate that the interchain distance, the quantities of phenyl ether, and the position of the substitute are factors that not only affected the thermal performance of polyimide by improving the molecular ?exibility but also reduced the dielectric constant of polyimide by increasing the free volume of the molecular chain and decreasing the polarization points per unit volume.
关键词： dielectric properties,copolymers,polyimides,films
更新于2025-09-23 15:23:52
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Multi-stimuli responsive novel polyimide smart materials bearing triarylamine and naphthalimide groups
摘要： Multiple stimuli-responsive smart polymers have received increasingly attention in recent years. In this work, a series of novel polyimides (PIs) bearing triarylamine and naphthalimide perssad were devised and prepared. These novel polyimides are able to respond to four different stimuli (light, pH, explosives and voltage) and perform four functions (light detectors, electrochromism, fluorescence detectors and memory devices). Furthermore, the smart materials are suitable for complicated environment. This work will open a new route for the development of novel smart materials with multi-functional and multiple stimuli-responsive properties.
关键词： Polyimides,Triarylamine,Smart materials,Naphthalimide,Multi-stimuli responsive
更新于2025-09-23 15:23:52
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Synthesis and Characterization of Organo-Soluble Polyimides Derived from Alicyclic Dianhydrides and a Dihydroxyl-Functionalized Spirobisindane Diamine
摘要： Two organo-soluble polyimides were synthesized by reaction of alicyclic bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BC) or 1,4,7,8-tetrabromobicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic anhydride (BCBr4) with 3,3,3’,3’-tetramethyl-1,1’-spirobisindane-5,5’-diamino-6,6’-diol (SBIDA). BC-SBIDA and BCBr4-SBIDA showed thermal stability of up to ~420 and 352 °C and displayed microporosity as indicated by Brunauer-Emmett-Teller (BET) surface areas of 191 and 243 m2 g-1, respectively. The polyimides were solution processible in polar organic solvents and exhibited strong mechanical properties with tensile modulus of 1.15-1.4 GPa, tensile strength of 27-28 MPa, and elongation at break of 2-4%. Introducing alicyclic moieties disturbs the delocalization of π-electrons across the polyimide backbone that reduces formation of charge transfer complexes (CTCs) leading to formation of colorless and transparent polyimide films. A fresh film sample of the bromine substituted BCBr4-SBIDA showed oxygen permeability of 31 barrer and oxygen/nitrogen selectivity of 5.9. Long-term physical aging of BCBr4-SBIDA over 365 days resulted in decrease of O2 permeability to 17 barrer with a simultaneous boost in O2/N2 selectivity to 6.6, which demonstrated highly competitive performance compared to commercially available polymers for air separation.
关键词： alicyclic dianhydrides,membrane,polyimides,gas separation,optical properties,intrinsic microporosity
更新于2025-09-04 15:30:14
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A sol-gel polymerization method for creating nanoporous polyimide silsesquioxane nanostructures as soft dielectric materials
摘要： A sol–gel polymerization method was developed to make polyimide (PI) silsesquioxane (SSQ) nanoparticles as functional, soft dielectric materials. The surface functionalization of the polymer chain backbone and chain ends of poly(trimellitic anhydride chloride-co-4,40-methylenedianiline), PMR-15 resin, with para-(chloromethyl)-phenylethyltrimethoxy silane yielded a novel sol–gel reactive sites functionalized PMR-silane precursor. Upon base-catalyzed hydrolysis and condensation of the PMR-silane precursor, spherical, raspberry-like PMR-SSQ nanoparticles were obtained in considerably good yield. Controlling the particle size distribution was attempted upon adjusting the molar ratio between the silane precursor and the base, as well as in the presence of a catalytic amount of silica sols. Particle composition, thermal stability, and morphology were confirmed from Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy analyses. Nanoparticles, visualized under transmission electron microscopy exhibit a nanoporous structure. The Brunauer–Emmett–Teller analysis confirmed that the average pore dimension is ranged from 2 to 5 nm. The dielectric constant of PMR-SSQ nanoparticles was as low as 1.95, compared to dielectric constants of 3.05 and 3.13 for PMR-15 and PMR-silane, respectively. Thus, the base-catalyzed sol–gel polymerization of alkoxysilylated PI offers a novel synthetic path to make functional nanoporous PI nanostructures that possess ultralow dielectric constants.
关键词： resin,polyimides,polymer functionalization,soft dielectric materials,thermoplastics
更新于2025-09-04 15:30:14