Naphthalene Phthalimide Derivatives as Model Compounds for Electrochromic Materials

Electrochromism of organic compounds is a well-known phenomenon; however, nowadays, most research is focused on anodic coloring materials. Development of efficient, cathodic electrochromic materials is challenging due to the worse stability of electron accepting materials compared with electron donating ones. Nevertheless, designing stable cathodic coloring organic materials is highly desired-among other reasons-to increase the coloration performance. Hence, four phthalimide derivatives named 1,5-PhDI, 1,4-PhDI, 2,6-PhDI and 3,3'-PhDI were synthesized and analyzed in depth. In all cases, two imide groups were connected via naphthalene (1,5-PhDI, 1,4-PhDI, 2,6-PhDI) or 3,3'-dimethylnaphtidin (3,3'-PhDI) bridge. To observe the effect of chemical structure on physicochemical properties, various positions of imide bond were considered, namely, 1,5- 1,4- and 2,6-. Additionally, a compound with the pyromellitic diimide unit capped with two 1-naphtalene substituents was obtained. All compounds were studied in terms of their thermal behavior, using differential calorimetry (DSC) and thermogravimetric analysis (TGA). Moreover, electrochemical (CV, DPV) and spectroelectrochemical (UV-Vis and EPR) analyses were performed to evaluate the obtained materials in terms of their application as cathodic electrochromic materials. All obtained materials undergo reversible electrochemical reduction which leads to changes in their optical properties. In the case of imide derivatives, absorption bands related to both reduced and neutral forms are located in the UV region. However, importantly, the introduction of the 3,3'-dimethylnaphtidine bridge leads to a noticeable bathochromic shift of the reduced form absorption band of 3,3'-PhDI. This indicates that optimization of the phthalimide structure allows us to obtain stable, cathodic electrochromic materials.

From gas separation to ion transport in the cavity of hyperbranched polyamides based on triptycene aimed for electrochromic and memory devices

Introducing 3D triptycene as core with methoxy-diphenylamine into hyper- branching polyamides will greatly improve robust electrochemical cycling stability crucial for the application of ECDs.

Fluorescent Labeling to Investigate Nanopatterning Processes in Extreme Ultraviolet Lithography

Extreme ultraviolet (EUV) lithography uses 13.5 nm light to reach the sub-20 nm resolution. However, the process of pattern formation induced by this high-energy light is not well-understood. In this work, we provide an inorganic EUV photoresist with fluorescence properties by introducing a carbazole derivative as a ligand, and we study its effect on the patterning process. Using the fluorescence properties, changes in the emission of the material after EUV exposure could be tracked by means of spectroscopy and microscopy. The resist sensitivity was substantially reduced by the incorporation of the carbazole benzoate ligands, which is attributed to hole trapping and steric hindrance. After EUV irradiation of the resist films, infrared, UV-visible absorption, and fluorescence spectroscopies showed that the carbazole units were still mostly intact, although their fluorescence intensity was lowered. Our work shows that fluorescent labeling can provide relevant mechanistic insights in the patterning process of resists, potentially with a molecular resolution.

Synthesis and Gas-Permeation Characterization of a Novel High-Surface Area Polyamide Derived from 1,3,6,8-Tetramethyl-2,7-diaminotriptycene: Towards Polyamides of Intrinsic Microporosity (PIM-PAs)

A triptycene-based diamine, 1,3,6,8-tetramethyl-2,7-diamino-triptycene (TMDAT), was used for the synthesis of a novel solution-processable polyamide obtained via polycondensation reaction with 4,4'-(hexafluoroisopropylidene)bis(benzoic acid) (6FBBA). Molecular simulations confirmed that the tetrasubstitution with ortho-methyl groups in the triptycene building block reduced rotations around the C⁻N bond of the amide group leading to enhanced fractional free volume. Based on N₂ sorption at 77 K, 6FBBA-TMDAT revealed microporosity with a Brunauer⁻Emmett⁻Teller (BET) surface area of 396 m² g-1; to date, this is the highest value reported for a linear polyamide. The aged 6FBBA-TMDAT sample showed moderate pure-gas permeabilities (e.g., 198 barrer for H₂, ~109 for CO₂, and ~25 for O₂) and permselectivities (e.g., αH₂/CH₄ of ~50) that position this polyamide close to the 2008 H₂/CH₄ and H₂/N₂ upper bounds. CO₂⁻CH₄ mixed-gas permeability experiments at 35 °C demonstrated poor plasticization resistance; mixed-gas permselectivity negatively deviated from the pure-gas values likely, due to the enhancement of CH₄ diffusion induced by mixing effects.

Electrochromic Devices Based on Poly(2,6-di(9H-carbazol-9-yl)pyridine)-Type Polymer Films and PEDOT-PSS

2,6-Di(9H-carbazol-9-yl)pyridine (DiCP) was synthesized and its corresponding homopolymer (PDiCP) and copolymers (P(DiCP-co-CPDT), P(DiCP-co-CPDT2), P(DiCP-co-CPDTK), and P(DiCP-co-CPDTK2)) were synthesized electrochemically. The anodic copolymer with DiCP:cyclopentadithiophene ketone (CPDTK) = 1:1 feed molar ratio showed high transmittance change (ΔT%) and colouration efficiency (η), which were measured as 39.5% and 184.1 cm² C-1 at 1037 nm, respectively. Electrochromic devices (ECDs) were composed of PDiCP, P(DiCP-co-CPDT), P(DiCP-co-CPDT2), P(DiCP-co-CPDTK), and P(DiCP-co-CPDTK2) as anodically-colouring polymers, and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) as cathodically-colouring polymers. P(DiCP-co-CPDTK)/PEDOT-PSS ECD showed light silverish-yellow at 0.0 V, light grey at 0.7 V, grey at 1.3 V, light greyish blue at 1.7 V, and greyish blue at 2.0 V. Moreover, P(DiCP-co-CPDTK)/PEDOT-PSS ECD presented high ΔT (38.2%) and high η (633.8 cm² C-1) at 635 nm.

Recent advances in triphenylamine-based electrochromic derivatives and polymers

Triphenylamine-containing electrochromic materials with great potential applications in low energy-consumption displays, light-adapting mirrors in vehicles, and smart windows have experienced an exponential growth of research interests. In this review, the newly developed triphenylamine-based derivatives and polymers are reviewed and elaborated.

Electrosynthesis of Aromatic Poly(amide-amine) Films from Triphenylamine-Based Electroactive Compounds for Electrochromic Applications

Two electropolymerizable monomers with a methoxytriphenylamine core linked via amide groups to two triphenylamine (TPA) or N-phenylcarbazole (NPC) terminal groups, namely 4,4'-bis(4-diphenylaminobenzamido)-4''-methoxytriphenylamine (MeOTPA-(TPA)₂) and 4,4'-bis(4-(carbazol-9-yl)benzamido)-4''-methoxytriphenylamine (MeOTPA-(NPC)₂), were synthesized and characterized by FTIR and ¹H NMR spectroscopy, mass spectrometry, and cyclic voltammetry. The electrochemical polymerization reactions of these MeOTPA-cored monomers over indium tin oxide (ITO) electrode allow the generation of electroactive poly(amide-amine) films. The electro-generated polymer films exhibited reversible redox processes and multi-colored electrochromic behaviors upon electro-oxidation, together with moderate coloration efficiency and cycling stability. The optical density changes (ΔOD) were observed in the range of 0.18⁻0.68 at specific absorption maxima, with the calculated coloration efficiencies of 42⁻123 cm²/C. Single-layer electrochromic devices using the electrodeposited polymer films as active layers were fabricated for the preliminary investigation of their electrochromic applications.

Poly(tris(4-carbazoyl-9-ylphenyl)amine)/Three Poly(3,4-ethylenedioxythiophene) Derivatives in Complementary High-Contrast Electrochromic Devices

A carbazole-based polymer (poly(tris(4-carbazoyl-9-ylphenyl)amine) (PtCz)) is electrosynthesized on an indium tin oxide (ITO) electrode. PtCz film displays light yellow at 0.0 V, earthy yellow at 1.3 V, grey at 1.5 V, and dark grey at 1.8 V in 0.2 M LiClO₄/ACN/DCM (ACN/DCM = 1:3, by volume) solution. The ΔT and coloration efficiency (η) of PtCz film are 30.5% and 54.8 cm²∙C-1, respectively, in a solution state. Three dual-type electrochromic devices (ECDs) are fabricated using the PtCz as the anodic layer, poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,3-dimethyl-3,4-dihydro-thieno[3,4-b][1,4]dioxepine) (PProDOT-Me₂), and poly(3,4-(2,2-diethylpropylenedioxy)thiophene) (PProDOT-Et₂) as the cathodic layers. PtCz/PProDOT-Me₂ ECD shows high ΔTmax (36%), high ηmax (343.4 cm²·C-1), and fast switching speed (0.2 s) at 572 nm. In addition, PtCz/PEDOT, PtCz/PProDOT-Me₂, and PtCz/PProDOT-Et₂ ECDs show satisfactory open circuit memory and long-term stability.

Functional Aromatic Polyamides

We describe herein the state of the art following the last 8 years of research into aromatic polyamides, wholly aromatic polyamides or aramids. These polymers belong to the family of high performance materials because of their exceptional thermal and mechanical behavior. Commercially, they have been transformed into fibers mainly for production of advanced composites, paper, and cut and fire protective garments. Huge research efforts have been carried out to take advantage of the mentioned characteristics in advanced fields related to transport applications, optically active materials, electroactive materials, smart materials, or materials with even better mechanical and thermal behavior.

A novel red to transmissive electrochromic polymer based on phenanthrocarbazole

This work describes the synthesis of a novel red to transmissive electrochromic polymer with high optical contrast and fast switching times.