Self-assembly Technique Research Articles

Combined Swelling and Metal Infiltration: Advancing Block Copolymer Pattern Control for Nanopatterning Applications.

Block copolymer (BCP) patterning is a well-established self-assembly technique for developing surfaces with regular and controllable nanosized features. This method relies on the microphase separation of a BCP film and subsequent infiltration with inorganic species. The BCP film serves as a template, leaving behind inorganic replicas when removed. BCP patterning offers a promising, cost-effective alternative to standard nanopatterning techniques, featuring fewer processing steps and reduced energy use. However, BCP patterning can be complex and challenging to control. Varying the structural characteristics of the polymeric template (feature sizes) requires careful and often challenging synthesis of bespoke BCPs with controllable molecular weights (M w). To develop BCP patterning as a standard nanofabrication approach, a vapor-phase patterning (VPP) technology has been developed. VPP allows for the simultaneous, single-step, selective swelling of BCP nanodomains to precise feature sizes and morphologies while forming inorganic features by metallic precursor infiltration. Infiltration preserves the swollen arrangement, thus allowing for feature size selection without synthesizing BCPs with different M w, simplifying the process. VPP has the potential to revolutionize nanopatterning techniques in industries such as optical materials, materials for energy storage, sensors, and semiconductors by providing a pathway to efficient, precise, and cost-effective BCP template patterning.

Bioconjugation of Podophyllotoxin and Nanosystems: Approaches for Boosting Its Biopharmaceutical and Antitumoral Profile

Podophyllotoxin is a natural compound belonging to the lignan family and is well-known for its great antitumor activity. However, it shows several limitations, such as severe side effects and some pharmacokinetics problems, including low water solubility, which hinders its application as an anticancer agent. Over the past few years, antitumor research has been focused on developing nanotechnology-based medicines or nanomedicines which allow researchers to improve the pharmacokinetic properties of anticancer compounds. Following this trend, podophyllotoxin nanoconjugates have been obtained to overcome its biopharmaceutical drawbacks and to enhance its antitumor properties. The objective of this review is to highlight the advances made over the past few years (2017–2023) regarding the inclusion of podophyllotoxin in different nanosystems. Among the huge variety of nanoconjugates of diverse nature, drug delivery systems bearing podophyllotoxin as cytotoxic payload are organic nanoparticles mainly based on polymer carriers, micelles, and liposomes. Along with the description of their pharmacological properties as antitumorals and the advantages compared to the free drug in terms of biocompatibility, solubility, and selectivity, we also provide insight into the synthetic procedures developed to obtain those podophyllotoxin-nanocarriers. Typical procedures in this regard are self-assembly techniques, nanoprecipitations, or ionic gelation methods among others. This comprehensive perspective aims to enlighten the medicinal chemistry community about the tendencies followed in the design of new podophyllotoxin-based drug delivery systems, their features and applications.

Atomically thin high-entropy oxides via naked metal ion self-assembly for proton exchange membrane electrolysis

Designing efficient Ruthenium-based catalysts as practical anodes is of critical importance in proton exchange membrane water electrolysis. Here, we develop a self-assembly technique to synthesize 1 nm-thick rutile-structured high-entropy oxides (RuIrFeCoCrO2) from naked metal ions assembly and oxidation at air-molten salt interface. The RuIrFeCoCrO2 requires an overpotential of 185 mV at 10 m A cm−2 and maintains the high activity for over 1000 h in an acidic electrolyte via the adsorption evolution mechanism. We discuss the role of each element in the RuIrFeCoCrO2 and find that the Cr, Co, and Ir sites contribute to the catalytic activity, while the Cr atoms weaken the Ru-O bond covalency and improves the catalyst stability. The assembled proton exchange membrane electrolyzer operates stably for more than 600 h at a large current of 1 A cm−2. The naked ion assembly demonstrated in this work may provide an effective pathway for the controlled synthesis of a diversity of high-entropy materials.

Ultrafast humidity sensor and transient humidity detections in high dynamic environments

Limited by the adsorption and diffusion rate of water molecules, traditional humidity sensors, such as those based on polymer electrolytes, porous ceramics, and metal oxides, typically have long response times, which hinder their application in monitoring transient humidity changes. Here we present an ultrafast humidity sensor with a millisecond-level response. The sensor is prepared by assembling monolayer graphene oxide quantum dots on silica microspheres using a simple electrostatic self-assembly technique. Benefiting from the joint action of the micro spheres and the ultrathin humidity-sensitive film, it displays the fastest response time (2.76 ms) and recovery time (12.4 ms) among electronic humidity sensors. With the ultrafast response of the sensor, we revealed the correlation between humidity changes in speech airflow and speech activities, demonstrated the noise immunity of humidity speech activity detection, confirmed the humidity shock caused by explosions, realized ultrahigh frequency respiratory monitoring, and verified the effect of humidity-triggering in the non-invasive ventilator. This ultrafast humidity sensor has broad application prospects in monitoring transient humidity changes.

MX/MWCNTs composite material aids new strategy for HBV-DNA electrochemical biosensor: achieving multi-level signal amplification and unlabeled detection

Hepatitis B virus DNA (HBV-DNA) serves as a crucial biomarker for the detection of the hepatitis B virus, with variations in its concentration in blood samples providing vital insights into patient infection and recovery status. We have developed an electrochemical biosensor tailored for HBV-DNA detection, exhibiting high sensitivity, specificity, and a broad detection range. The biosensor utilizes a composite material composed of MXene and multiwalled carbon nanotubes (MX/MWCNTs), prepared through a hand-shaking self-assembly technique, to modify the glassy carbon electrode (GCE) and serve as signal receivers. A meticulously designed padlock probe DNA specifically recognizes HBV-DNA and forms a double-stranded DNA structure, which is subsequently degraded by exonuclease III. The resulting sequence then hybridizes with a PolyT-primer to create template, triggering rolling circle amplification and releasing a substantial amount of pyrophosphate for the initial level of signal amplification. Subsequently, the pyrophosphate induces the release of methylene blue (MB) from MB@ZIF-90 composite, achieving a second level of signal amplification. The released MB is then adsorbed by the MX/MWNCNTs-modified GCE, which possesses cationic dye adsorption capabilities and a large specific surface area, generating a detection signal and completing the third level of amplification. This biosensor offers a detection range spanning from 1.0 pM to 1.0 × 106 pM, with a remarkable detection limit as low as 0.5 pM (3σ/S), and is capable of distinguishing base mismatches. Furthermore, it has demonstrated excellent specificity and recovery performance in serum testing. The performance of this biosensor demonstrates significant potential for clinical application, with the ultimate goal of improving the diagnosis and management of hepatitis B.Graphical

PH-sensitive Silk Fibroin Nanoparticles Encapsulating Β-Hydroxyisovalerylshikonin for Targeted Pancreatic Cancer Therapy.

Pancreatic cancer is a highly malignant tumor with a poor prognosis, and current treatment methods have limited effectiveness. Therefore, developing new and more effective therapeutic strategies is crucial. This study aims to establish pH-responsive silk fibroin (SF) nanoparticles encapsulating β-hydroxyisovalerylshikonin (SF@β-HIVS) to enhance the therapeutic effects against pancreatic cancer. SF@β-HIVS nanoparticles were prepared using a self-assembly technique and characterized under different pH conditions using scanning electron microscopy (SEM) and dynamic light scattering (DLS). The effects of SF@β-HIVS on the viability, apoptosis, and migration of PANC-1 cells were assessed through in vitro experiments. Additionally, in vivo experiments using a PANC-1 xenograft mouse model evaluated the antitumor activity and biosafety of SF@β-HIVS. SF@β-HIVS nanoparticles exhibited a uniformly distributed spherical structure under pH 7.4 conditions and rapidly disintegrated in acidic environments, releasing the drug. In vitro experiments demonstrated that SF@β-HIVS significantly inhibited PANC-1 cell proliferation, induced apoptosis, and suppressed cell migration. In vivo, experiments confirmed the significant antitumor activity and good biosafety of SF@β-HIVS. This study successfully developed pH-responsive SF@β-HIVS nanoparticles and validated their potential in treating pancreatic cancer. These findings provided a foundation for the clinical application of SF@β-HIVS in pancreatic cancer treatment.

Tribological Behavior of Friction-Stir-Processed Nanocomposite Prepared Through Self-Assembled Monolayer Technique

An attempt was made to use friction stir processing, a manufacturing technique usually employed for the fabrication of nanocomposites. For the substrate, AA7075 was used and for dispersed phase, B4C nanoparticles of size (<30 nm) were selected. Nanocomposite samples were fabricated using three different tool rotation speeds of 1000, 1200, and 1400 rpm, by keeping other process parameters as constant, and their influence on the nanocomposite was judged by the study of tribological behavior and microhardness. This research work aims at the self-assembled monolayer formation of B4C nanoparticles homogeneous layer into a substrate material and hence minimizing the quantity of nanoparticles required in the preparation of nanocomposites via FSP. The results in terms of increased microhardness compared to the substrate material are reflected by the sample processed at the tool rotation of 1200 rpm. The average microhardness was found out to be 195 Hv compared to the substrate material. There is a maximum increment attained in wear resistance upto 46.7% in the sample processed at 1200 rpm. Worn out surface morphology were analyzed through scanning electron microscopy, and X-ray diffraction was also undertaken to analyze the presence of reinforcement particle in the fabricated nanocomposites.

Hydrophobic dual-polymer-reinforced graphene composite aerogel for efficient water-oil separation.

Addressing the environmental challenges posed by oil spills and industrial wastewater is critical for sustainable development. Graphene aerogels demonstrate significant potential as highly efficient adsorbents due to their high specific surface area, excellent structural tunability and outstanding chemical stability. Among available fabrication methods, the hydrothermal self-assembly technique stands out for its low cost, high tunability and good scalability. However, brittleness caused by stacking and agglomeration of graphene layers during self-assembly remains a significant challenge. In this study, we present a green and efficient self-assembly strategy combining a one-step hydrothermal process with a solution immersion method to fabricate a PDMS-coated epoxidized natural rubber-graphene composite aerogel (P@EGA). The resulting aerogel exhibits a high specific surface area (482.362 m2 g-1), hierarchical pore distribution from microporous to macroporous, ultra-low density (0.0104 g cm-3) and excellent hydrophobicity (contact angle = 147.6°). Remarkably, it retains 97.54% of its compressive stress after 50 compression-release cycles at 80% strain and quickly recovers its shape under a 500 g load. The P@EGA aerogel demonstrates outstanding adsorption capacities (65.37-132.75 g g-1) for various oils and organic solvents, complete oil absorption in 0.4 seconds, and effortless regeneration through simple squeezing. Furthermore, its dual functionality in gravity-driven and powered water-oil separation systems underscores its broad application potential in environmental remediation.

Generating Strong Circularly Polarized Luminescence from Self-assembled Films of Chiral Selenium Nanoparticles and Upconversion Nanoparticles.

Circularly polarized luminescence (CPL) has garnered significant research attention. Achieving a high luminescence dissymmetry factor (glum) is a key challenge in this field. Herein, we reported, for the first time, the fabrication of a chiral assembled film consisting of chiral D-/L-Selenium nanoparticles (D-/L-Se NPs) and DSPE-PEG-NH2 modified upconversion nanoparticles (DPNUCNPs) with remarkable CPL properties that were generated by the interfacial self-assembly technique. The chiral Se/DPNUCNPs films, consisting of three layers (3L) of D-/L-Se films and 3L DPNUCNPs films, exhibited the highest circular dichroism (CD) response and the strongest CPL signals. Under laser excitation at 980 nm, the 3L D-/L-Se/3L DPNUCNPs assembled films displayed symmetric CPL signals between 400 and 600 nm, with a maximum |glum| value of 0.68. The interaction between DPNUCNPs and Se NPs involves energy transfer and chirality transfer, along with the formation of spin-polarized excitons, thereby resulting in CPL activity. Furthermore, the chiral Se/DPNUCNPs films were patterned for anti-counterfeit and encryption applications. Our study provides a novel guide for fabricating chiral nanomaterials with strong CPL response.

Enhanced Stability and In Vitro Biocompatibility of Chitosan-Coated Lipid Vesicles for Indomethacin Delivery.

Lipid vesicles, especially those utilizing biocompatible materials like chitosan (CHIT), hold significant promise for enhancing the stability and release characteristics of drugs such as indomethacin (IND), effectively overcoming the drawbacks associated with conventional drug formulations. This study seeks to develop and characterize novel lipid vesicles composed of phosphatidylcholine and CHIT that encapsulate indomethacin (IND-ves), as well as to evaluate their in vitro hemocompatibility. The systems encapsulating IND were prepared using a molecular droplet self-assembly technique, involving the dissolution of lipids, cholesterol, and indomethacin in ethanol, followed by sonication and the gradual incorporation of a CHIT solution to form stable vesicular structures. The vesicles were characterized in terms of size, morphology, Zeta potential, and encapsulation efficiency and the profile release of drug was assessd. In vitro hemocompatibility was evaluated by measuring erythrocyte lysis and quantifying hemolysis rates. The IND-ves exhibited an entrapment efficiency of 85%, with vesicles averaging 317.6 nm in size, and a Zeta potential of 24 mV, indicating good stability in suspension. In vitro release kinetics demonstrated an extended release profile of IND from the vesicles over 8 h, contrasting with the immediate release observed from plain drug solutions. The hemocompatibility assessment revealed that IND-ves exhibited minimal hemolysis, comparable to control groups, indicating good compatibility with erythrocytes. IND-ves provide a promising approach for modified indomethacin delivery, enhancing stability and hemocompatibility. These findings suggest their potential for effective NSAID delivery, with further in vivo studies required to explore clinical applications.

Antibacterial and osteogenic gain strategy on titanium surfaces for preventing implant-related infections.

Infection and insufficient osseointegration are the primary factors leading to the failure of titanium-based implants. Surface coating modifications that combine both antibacterial and osteogenic properties are commonly employed strategies. However, the challenge of achieving rapid antibacterial action and consistent osteogenesis with these coatings remains unresolved. In this study, a functional composite coating (PDA/PPy@Cu/Dex) was prepared on titanium surfaces using layer-by-layer self-assembly and electrochemical deposition techniques. The hydroxyl groups grafted by polydopamine's (PDA) self-polymerization and the enhanced conductivity and uniform electric field distribution provided by polypyrrole (PPy) allowed for the even dispersion of copper nanoparticles and dexamethasone (Dex) on the titanium surface. This synergistically coupled the photothermal ion antibacterial properties of copper nanoparticles with the osteogenic promotion of dexamethasone. In vitro antibacterial experiments revealed that the heat generated by photothermal effects and reactive oxygen species enhanced the antibacterial activity of copper ions, reducing the antibacterial time to six h and achieving antibacterial enhancement. In vitro cell experiments showed that the long-term slow release of copper ions and dexamethasone enhanced the osteogenic differentiation of stem cells, thereby achieving osteogenic benefits. Moreover, in vivo toxicity experiments demonstrated that the composite coating had no adverse effects on normal tissues. Therefore, the antibacterial and osteogenic enhancement strategy for titanium surfaces presented in this study offers a new potential approach for preventing implant-associated infections.

Recycling self-assembled colloidal quantum dot supraparticle lasers

Supraparticles comprising semiconductor colloidal quantum dots as building blocks are a new class of microscopic lasers with a wide host of applications, including photocatalysis, biological and environmental sensing, integrated photonics, and medicine. Despite the recent advances in their fabrication, there have been no reports of their quantum dot components being recovered for use in a circular economy. Herein, we demonstrate a novel method for the recycling of these whispering-gallery-mode supraparticle lasers with a quantum dot recovery yield of 85%. The photoluminescence quantum yield of the recycled quantum dots is retained at 83 ± 16% from the initial batch of 86 ± 9%. These recycled quantum dots are then used again to synthesize distinct supraparticles via an oil-in-water emulsion self-assembly technique, allowing for the recreation of lasing supraparticles with similar thresholds to their freshly made precursors at 32.8 ± 8.2 mJ·cm-2 and 34.8 ± 8.6 mJ·cm-2, respectively. This proof-of-concept for recyclability has the potential to complement and enhance the manufacturing of supraparticle lasers, as well as to contribute to the overall recycling efforts of a broad spectrum of colloidal nanoparticle species, aiming to improve the economic and environmental sustainability of the technology.

The Lattice Mismatch-Driven Photochemical Self-Assembly of Supported Heterostructures for Stable and Enhanced Electrocatalytic Carbon Dioxide Reduction Reaction.

Metallic heterostructural nanocrystals (HNCs) hold immense potential in electrocatalytic carbon dioxide reduction reaction (CO2RR) owing to their abundant active sites and high intrinsic activity. However, a significant challenge still remains in achieving controlled nucleation and growth sites for HNCs on supports and comprehending the influence of the structure-activity relationship on electrocatalytic CO2RR performance. This work presents a photochemical self-assembly technique without the necessity for reducing agents or facet-specific capping agents. By controlling lattice mismatch and manipulating transfer paths of photo-generated carriers, we can precisely direct the growth sites and nucleation of nanocrystals, enabling the self-assembly of supported core-shell and Janus nanostructures. Compared to Pd(T)@Au core-shell HNCs with the same loading, Pd cube-Au Janus HNCs exhibit significantly enhanced selectivity and stability toward carbon monoxide (CO) production in CO2RR at less negative potentials. The Pd cube-Au Janus HNC electrocatalyst achieved a Faradaic efficiency (FE) of 92.6 ± 3.5% for CO electroreduction, accompanied by a current density of 72.3 mA·cm-2 at -0.58 V. This work provides an effective strategy for designing advanced supported tandem electrocatalysts to boost the selectivity and durability test of CO2RR.

Catalyst-free in-plane growth of high-quality ultra-thin InSb nanowires

InSb nanowires (NWs) show an important application in topological quantum computing owing to their high electron mobility, strong spin–orbit interaction, and large g factor. Particularly, ultra-thin InSb NWs are expected to be used to solve the problem of multiple sub-band occupation for the detection of Majorana fermions. However, it is still difficult to epitaxially grow ultra-thin InSb NWs due to the surfactant effect of Sb. Here, we develop an in-plane self-assembled technique to grow catalyst-free ultra-thin InSb NWs on Ge(001) substrates by molecular-beam epitaxy. It is found that ultra-thin InSb NWs with a diameter as small as 17 nm can be obtained by this growth manner. More importantly, these NWs have aspect ratios of 40–100. We also find that the in-plane InSb NWs always grow along the [110] and [11¯0] directions, and they have the same {111} facets, which are caused by the lowest-surface energy of {111} crystal planes for NWs grown with a high Sb/In ratio. Detailed structural studies confirm that InSb NWs are high-quality zinc blende crystals, and there is a strict epitaxial relationship between the InSb NW and the Ge substrate. The in-plane InSb NWs have a similar Raman spectral linewidth compared with that of the single-crystal InSb substrate, further confirming their high crystal quality. Our work provides useful insights into the controlled growth of in-plane catalyst-free III–V NWs.

Quinone Quest: Unraveling electrochemical performance in quinone-anchored 3D graphene architectures for high-energy supercapacitors

In the pursuit of advancing energy storage technologies, the exploration of novel electrode materials for supercapacitors, specifically organic materials, has garnered significant attention. This work delves into the electrochemical performance of quinone-anchored three-dimensional (3D) graphene (3DG) architectures as potential electrode materials for high-energy supercapacitors, focusing on elucidating the influence of different quinone types including 1,4-naphthoquinone (NQ), anthraquinone (AQ), duraquinone (DQ), p-benzoquinone (BQ), 2,5-dimethyl-1,4-benzoquinone (DMBQ), and sodium anthraquinone-2-sulfonate (SAQS). To that end, various quinone-anchored three-dimensional graphene (Q_3DG) architectures were synthesized via a chemical reduction-induced self-assembly technique in the presence of l-ascorbic acid, a green reducing agent. The physicochemical characterizations confirmed the successful incorporation of quinones to the carbon structure, without the presence of any impurities. Different interaction mechanisms between graphene oxide (GO) and quinone molecules during the synthesis led to different surface morphologies, which affected their electrochemical behavior. The 3-electrode electrochemical characterizations in 1.0 M Na2SO4 electrolyte revealed that all Q_3DG structures exhibited superior electrochemical performance compared to GO, as well as to a Bare_3DG sample synthesized without quinone molecules. NQ anchored 3DG (NQ_3DG) network yielded the highest specific capacitance value of 386.3 F.g−1 at 10 mV.s−1, which was almost 50 times larger than that of Bare_3DG. The findings not only shed light on the fundamental mechanisms governing charge storage and transfer within these unique architectures but also provide valuable insights for the rational and green design of next-generation organic electrode-based supercapacitors with enhanced energy storage capabilities.

Fabrications of Au–Pt Bimetallic Heterostructure Electrodes By Ligand-Exchange Assisted Layer-By-Layer Self-Assembly for Hydrogen Evolution Reaction

Platinum (Pt) is a widely utilized electrocatalyst for hydrogen evolution reaction (HER) for water splitting, since the Pt–H bond strength is optimal for hydrogen adsorption and desorption for HER. In order to improve its catalytic activity and stability, previous research reported various types of preparation methods for Pt-containing bimetallic catalysts with noble metals (Ru, Pd, Ag, and Au) or transition metals (Cr, Mn, Fe, Co, Ni, Cu, and Zn) with exhibitions of electronic and bifunctional effects. Among such examples, Au–Pt bimetallic electrocatalysts indicated several advantages, such as d-band shift of active element of Pt lowering binding strength of protons, shifting Pt oxidation potential for improved stability, and increased electron transfer. These catalysts were synthesized by seeded growth, galvanostatic deposition, surface dealloying, and electrodeposition methods. Nevertheless, a facile and effortless synthesis approach must be established to realize large-scale production of multicomponent catalysts.In this study, ligand-exchange assisted layer-by-layer (LbL) self-assembly method was utilized to prepare Au–Pt nanocomposite films for HER electrocatalyst. The ligand-exchange assisted LbL self-assembly technique was used to fabricate metallic nanoparticle (NP) thin films to reduce the amount of insulating organic components, and improves electrical conductivity through metal fusion between metal NPs. Tetraoctylammonium bromide (TOA-Br) ligands on the surface of Au and Pt nanoparticles (NPs) are alternately deposited onto Ti electrodes paired with diethylenetriamine (DETA), a short alkyl amine. This process is accompanied by the removal of the pre-attached bulky surface ligands of TOA-Br. The resulting Au and Pt NP LbL nanocomposite films are characterized by uniform thin-film depositions with a metal-level electrical conductivity (8.7 × 104 S cm-1), which is similar to the bulk metal conductivity. The Au–Pt NP nanocomposite films exhibited 80 mV at a current density of 10 mA cm-2 of HER overpotential under an acidic condition of 0.5 M H2SO4, which corresponds to one-third of that of the control sample of only Pt NP LbL film. The Au–Pt LbL film indicates competitive overpotential (less than 100 mV) despite the ultra-small amount of Pt contents (0.73 wt%), which is suggestive of enhanced catalytic activity. Higher activity could be ascribed to the synergistic effect of bimetallic heterostructure films with the d-band shift, superb electrical conductivity, rapid charge transfer, and increased electrochemical surface area. The suggested synthesis approach is expected to be effective for the fabrications of various electocatalystic thin films for various energy conversion devices.

The electrochemical performance deterioration mechanism of LiNi0.83Mn0.05Co0.12O2 in aqueous slurry and a mitigation strategy

Integrating high-nickel layered oxide cathodes with aqueous slurry electrode preparation routes holds the potential to simultaneously meet the demands for high energy density and low-cost production of lithium-ion batteries. However, the influence of dual exposure to air and liquid water as well as the heating treatment during aqueous slurry electrode processing on the high-nickel layered oxide electrode is yet to be understood. In this study, we systematically investigate the structural evolution and electrochemical behaviors when LiNi0.83Mn0.05Co0.12O2 (NMC83) is subjected to aqueous slurry processing. It was observed that the crystal structure near the surface of NMC83 is partially reconstructed to contain a mixture of rock-salt and layered phases when exposed to water, leading to the deteriorated rate capability of the NMC83 electrodes. This partial surface reconstruction layer completely converts into a pure rock-salt phase upon cycling, accompanied by the release of O2, Ni leaching, catalyzed decomposition of the electrolyte, and the formation of a thick cathode electrolyte interphase layer. The byproducts of the electrolyte and dissolved Ni could shuttle to the Li metal side, causing a crosstalk effect that results in a thick and unstable solid electrolyte interphase layer on the Li surface. These in combination severely undermined the cycling stability of the NMC83 electrodes obtained from the aqueous slurry. A mitigation strategy using molecular self-assembly technique was demonstrated to enhance the surface stability of water-treated NMC83. Our findings offer new insights for tailoring ambient environment stability and aqueous slurry processability for ultra-high nickel layered oxide and other water-sensitive cathode materials.

Spatially-confined self-assembly boron nitride nanosheet interlayer in polymer nanocomposites significantly enhances the Capacitive energy storage performance

High-performance electrostatic capacitors are urgently needed of advanced electronic devices. Traditional nanodielectric designs, such as polyvinylidene fluoride (PVDF)-based nanocomposites with uniformly distributed nanofillers, necessitate laborious filler interface modification and yield limited energy density (Ue) and efficiency (η). Herein, boron nitride nanosheet (BNNS) intercalated polymer nanocomposites were innovatively prepared by plasma treatment and BNNS spatially-confined self-assembly techniques. The oriented dense interlayered BNNS substantially suppresses leakage current and bolsters the breakdown strength of nanocomposite films, outperforming randomly or oriented distributed BNNS systems, thus obtaining a higher Ue of ∼24.1 J/cm3. Moreover, the relaxation loss of PVDF could be effectively mitigated by polymethyl methacrylate and trace intercalated BNNS, maintaining an ultrahigh η (76 %) at 600 MV/m and greatly enhances the energy storage performance. Significantly, this newly designed nanocomposites necessitate only traces of BNNS (0.2 wt%) without filler-surface-modification. These findings afford insight into the programming and manufacture of high-performance electrostatic capacitors.

Unique and efficient modulation of polycarbazole thin film surface morphology by electrochemical, photochemical and self-assembly techniques

Surface morphology significantly impacts the performance of conducting polymers by influencing charge transport, electromechanical properties, and diffusion dynamics. Understanding and controlling surface morphology is crucial for optimizing the performance of conducting polymers in various applications. In this work, we synthesized for the first time the Azo-SH molecule containing azobenzene, thiol and carbazole groups, thus enabling it photoactivity, electroactivity and self-assembly properties. By integrating the photosensitive azobenzene and the thiol-terminated functional molecule into the electroactive carbazole group, it has been obtained unique surface morphologies that modulating effectively and efficiently via electrochemical, photochemical and self-assembly. The electroactive and photoactive polymer films obtained by electropolymerization were characterized by AFM, e-QCM, electrochemical impedance and XPS techniques. This study has demonstrated as a proof of concept that the surface properties of thin films formed with all-in-one type molecules can be modified by electrochemical, photochemical and self-assembly techniques. Surface morphology modulation of thin films by including wettability, polarity, dipole moment and other properties would provide a powerful approach to prepare functional organic devices.

Polymerization-Induced Self-Assembly for the Synthesis of Polyisoprene-Polystyrene Block and Random Copolymers: Towards High Molecular Weight and Conversion.

In this study, reversible addition-fragmentation chain- transfer (RAFT) polymerization combined with the polymerization-induced self-assembly (PISA) technique is used to synthesize polyisoprene (PI)-based block and random copolymers with polystyrene (PS), aiming for high molecular weight and monomer conversion. The focus is to optimize the polymerization conditions to overcome the existing challenge of cross-linking and Diels-Alder reactions during the polymerization of isoprene, which typically constrain the reaction conversion and molecular weight of the final polymers. Using a poly(methacrylic acid) (PMAA) macroRAFT agent synthesized in ethanol at 80°C, random and block copolymers of PS-PI with a target molecular weight of 50000gmole-1 and a high monomer conversion of ≈80% are achieved under optimized conditions in water-emulsion at 35°C. 1H nuclear magnetic resonance (NMR) verified the successful synthesis as well as the high content of 1,4 microstructure in polyisoprene. The thermal analysis via differential scanning calorimetry indicated distinct glass transitions for the microphase-separated PI-PS block copolymer, while a single transition for PI-PS random copolymer, indicating no microphase separation. Furthermore, dynamic light scattering analysis together with transmission electron microscopy provided further insight into the self-assembled emulsion nanoparticles of the polymers indicating a particle size in the range 70 to 130nm.