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Physical Vapor Deposited Films of a Perylene Derivative: Supramolecular Arrangement and Thermal Stability
摘要： The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 oC for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films.
关键词： perylene,PVD nanostructured films,thermal treatment,supramolecular arrangement
更新于2025-09-09 09:28:46
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Photoluminescent properties in perylene PVD films: Influence of molecular aggregates and supramolecular arrangement
摘要： Organic thin films are at the forefront of basic studies and applications in the field of physics, chemistry, biochemistry and materials science. For example, the intrinsic supramolecular arrangement, or simply the formation of aggregates may alter the optical and electrical properties, which would impact the potential applications of the material. Here, an attempt is made to correlate the molecular structures of two perylene derivatives, bis butylimido perylene (BuPTCD) and bis phenethylimido perylene (PhPTCD), with their film formation, in particular, the supramolecular arrangement and the photoluminescent properties. Emission spectra show that the PhPTCD has a radiative efficiency (RE) higher than that for BuPTCD when both are in solutions (monomers). Complementary, regarding PVD films, UV-Vis absorption measurements reveal that PhPTCD forms, predominantly, J aggregates, which are responsible for perylene derivative emission. However, BuPTCD PVD films are found to provide higher RE than PhPTCD PVD film. This apparent controversy could be explained considering other features such as crystallinity and molecular organization. The PVD film of BuPTCD is crystalline while PhPTCD PVD film is amorphous; BuPTCD has an edge-on while PhPTCD has a face-on molecular organization in PVD films.
关键词： perylene derivatives,PVD thin films,aggregates,photoluminescent properties,supramolecular arrangement
更新于2025-09-09 09:28:46
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Intrinsically recyclable and self-healable conductive supramolecular polymers for customizable electronic sensors
摘要： Electronic waste is increasing rapidly and ruining ecosphere owing to the growing amount of unrecyclable and even toxic electronic materials. Sensing components and electronic boards, mainly composed of unrecyclable metal oxides and thermoset polymers, are two major sources of electronic waste. Hence, developing novel electronic materials that can be fully recycled and reused is one of the most investigated concerns for recyclable electronics. In this study, efforts are devoted to inventing an intrinsically recyclable conductive supramolecular polymer, which is composed of a sensing segment of ionic liquid crosslinked by dynamic quadruple hydrogen bonds. This supramolecular polymer exhibits remarkable thermal sensing ability, reprocessability, and recyclability. Based on these advantages, it can be easily molded into an electronic thermometer with controllable size and shape, which can be fully recycled; also, it retains the same thermal sensing performance. Particularly, this supramolecular polymer can be processed into thermal sensing earplugs with customized 3D shapes for ear-temperature measurement as a reliable monitoring approach of body temperature. Thus, it offers great potential for practical applications in special conditions.
关键词： conductive supramolecular polymer,recyclable electronics,self-healing,customizable electronic sensors,thermal sensing
更新于2025-09-09 09:28:46
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Preparation of carbon dots decorated graphene/polyaniline composites by supramolecular in-situ self-assembly for high-performance supercapacitors
摘要： Supramolecular in-situ self-assembly is achieved to prepare carbon nanodots decorated graphene/polyaniline composites by adding β-cyclodextrin (β-CD) as the bonding agent in this work. With its unique structure, β-CD can form a supramolecular system with graphene oxide layers, generating the inclusion compound with aniline monomers, which makes the in-situ polymerization of polyaniline on the surface of graphene oxide. In the hydrothermal process, β-CD is carbonized to carbon nanodots anchored on the surface of reduced graphene oxide. The scanning electron microscopy (SEM) images show that the prepared reduced graphene oxide/carbon nanodots/polyaniline (RGO@CN/PANI) nanocomposites exhibit the micro morphology of a regular polyaniline particle array on the surface of graphene layers. The electrochemical tests demonstrate that the RGO@CN/PANI nanocomposites exhibit high specific capacitance (up to 871.8 F g-1 at 0.2A g-1), low charge transfer resistance (Rct), and presentable cycling performance (72% capacitance retention after 10000 cycles), indicating the satisfied performance for supercapacitors. The promising performance of RGO@CN/PANI can be attributed to the synergistic effect of RGO, carbon nanodots and PANI, as well as the regular microstructure in which the effective reaction area of polyaniline is increased and the rapid ion transport channel is provided.
关键词： β-cyclodextrin,supramolecular in situ self-assembly,Carbon dots modified Graphene,polyaniline
更新于2025-09-04 15:30:14
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Dynamically evolving surface patterns through light-triggered wrinkling erasure
摘要： For many applications, it is an imperative that changes in polymer surface topography, especially periodic patterns, can be triggered on command by a well-defined remote signal. In this contribution, we report a light-induced cascade of changes in wrinkling wavelengths on thin polymer layers supported by an elastomeric substrate under tensile stress. Through the applied supramolecular design, the effect of varying the ratio of light active and light passive components can be easily assessed, and it is shown that both the cascade type as well as the rate of the progress of the dynamic light-induced changes can be tuned by this ratio, as well as by the light intensity. Furthermore, for the reported phenomena to occur, nominally only every 20th polymer repeat unit needs to be occupied by a chromophore, which makes the conversion of the sub-nm photoisomerization reaction into 10 μm - scale changes of periodic surface patterns extremely efficient.
关键词： light-triggered wrinkling erasure,polymer surface topography,photoisomerization,supramolecular design,elastomeric substrate
更新于2025-09-04 15:30:14
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Ultrafast Dynamics of Encapsulated Molecules Reveals New Insight on the Photoisomerization Mechanism for Azobenzenes
摘要： Spatial con?nement can have a profound impact on the dynamics of chemical reactions, especially for isomerization reactions that involve large amplitude structural rearrangement of a molecule. This work uses ultrafast spectroscopy to probe the e?ects of con?nement on trans→cis photoisomerization following ππ? excitation of 4-propyl stilbene and 4-propyl azobenzene encapsulated in a supramolecular host-guest complex. Transient absorption spectroscopy of the encapsulated azobenzene derivative reveals the formation of two distinct excited-state species with spectral signatures resembling the cis and trans isomers. Formation of the cis species indicates a direct excited-state isomerization channel that is not observed in cyclohexane solution. Comparison with the stilbene analogue suggests that this “hot” excited-state isomerization pathway for encapsulated azobenzene involves primarily in-plane inversion, whereas a ten-fold increase of the excited-state lifetime for the trans isomer suggests that crowding in the capsule hinders isomerization from the relaxed S1 geometry of the trans isomer. This work provides new mechanistic insight on the relative roles of inversion and rotation in the ultrafast photoisomerization of azobenzene derivatives.
关键词： Azobenzenes,Encapsulated molecules,Supramolecular host-guest complex,Photoisomerization,Ultrafast dynamics
更新于2025-09-04 15:30:14
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Dynamic Diels–Alder reactions of maleimide–furan amphiphiles and their fluorescence ON/OFF behaviours
摘要： The occurrence of dynamic covalent reactions only requires relatively low activation energy, which allows both the forward and reverse reactions to proceed under mild conditions. Here, we report the design and synthesis of amphiphilic maleimide–furan adducts, where hydrophobic maleimide-based and hydrophilic furan-based moieties were connected by reversible dynamic covalent bonds. The Diels–Alder addition reactions of maleimide–furan adducts are simple, efficient, clean, and reversible without catalysts and side reactions, and occur under mild conditions. Single crystal X-ray diffraction revealed that the length of the dynamic covalent bonds is 1.56 ?, which is longer and weaker than for normal covalent bonds. The cleavage and reformation process of the dynamic covalent bonds was monitored by 1H NMR and fluorescence spectroscopy. 1H NMR spectroscopy revealed that the furan moieties of these new maleimide–furan amphiphiles can be exchanged in mixing systems due to dynamic Diels–Alder reactions; thus, two new maleimide–furan compounds can be transformed into each other. The maleimide–furan amphiphiles displayed reversible fluorescence ON/OFF behaviours and interesting H-bonding driven supramolecular assembly.
关键词： fluorescence ON/OFF behaviours,maleimide–furan adducts,Diels–Alder reactions,Dynamic covalent reactions,supramolecular assembly
更新于2025-09-04 15:30:14
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A three-dimensional Zn <sup>II</sup> coordination network based on 5,5′-methylenebis(2,4,6-trimethylisophthalic acid) and 2,7-bis(1 <i>H</i> -imidazol-1-yl)fluorene: synthesis, structure and luminescence properties
摘要： In recent years, coordination polymers constructed from multidentate carboxylate ligands and N-containing ligands have attracted much attention since these ligands can adopt a rich variety of coordination modes which can lead to crystalline products with intriguing structures and interesting properties. A new coordination polymer, namely poly[[diaqua[μ-2,7-bis(1H-imidazol-1-yl)fluorene-κ2N3:N3′][μ-5,5′-methylenebis(2,4,6-trimethylisophthalato)-κ2O1:O1′]zinc(II)] hemihydrate], {[Zn(C23H22O8)(C19H14N4)(H2O)2]·0.5H2O}n, 1, was prepared by the self-assembly of Zn(NO3)2·6H2O with 5,5′-methylenebis(2,4,6-trimethylisophthalic acid) (H4BTMIPA) and 2,7-bis(1H-imidazol-1-yl)fluorene (BIF) under solvothermal conditions. The structure of 1 was determined by elemental analysis, single-crystal X-ray crystallography, powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Each ZnII ion is six-coordinated by two O atoms from two H2BTMIPA2? ligands, by two N atoms from two BIF ligands and by two water molecules, forming a distorted octahedral ZnN2O4 coordination geometry. Adjacent ZnII ions are linked by H2BTMIPA2? ligands and BIF ligands, leading to the formation of a two-dimensional (2D) (4,4)-sql network, and intermolecular hydrogen-bonding interactions connect the 2D layer structure into the three-dimensional (3D) supramolecular structure. Each 2D layer contains two kinds of helices with the same direction, which are opposite in adjacent layers. The luminescence properties of complex 1 in the solid state have also been investigated.
关键词： crystal structure,fluorescence properties,two-dimensional coordination polymer,supramolecular,5,5′-methylenebis(2,4,6-trimethylisophthalic acid,zinc(II),2,7-bis(1H-imidazol-1-yl)fluorene,hydrogen bonding
更新于2025-09-04 15:30:14