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An acid-base bifunctional zeolitic imidazolate framework catalyst (ZIF8-A61-SO3H) with amine and sulfonic acid groups was successfully prepared through simple two step post-synthetic modification: preparation of amine-functionalized ZIF-8 with amine contents of 61% (ZIF8-A61) by the ligand exchange of 2-mIM with 3-amino-1,2,4-triazole (Atz), followed by the sulfonic acid functionalization by the ring-opening reaction of 1,3-propanesultone with –NH2 groups in ZIF8-A61. Amine-functionalized ZIF8-A materials with difference amine contents (15%, 34%, and 61%, respectively) were also prepared by controlling the synthesis time. All obtained ZIF catalysts evaluated as a heterogeneous catalyst for one-pot deacetalization-Knoevenagel condensation tandem reaction. Compared with ZIF-8 and amine-functionalized ZIF-8 catalysts, ZIF8-A61-SO3H catalyst showed good catalytic performance with 100% conversion of the reactant and 98% selectivity of the final Knoevenagel product. An enhanced catalytic activity can be attributed to the co-existence of site-isolated acid-base groups on the ZIF8-A61-SO3H catalyst in close proximity. The heterogeneous nature of the catalytic system was confirmed by a hot-filtering test and the catalyst also exhibited reusable in the five repeated cycles. A plausible catalytic mechanism of deacetalization-Knoevenagel condensation reaction over ZIF8-A61-SO3H was also proposed.

A catalytic hydrolysis rate of nerve agents can be a significant issue because of their severe toxicity which can lead to severe damage to human life. Regarding the issue, much effort has been given rise to the development of the various design of Zr(IV)-based MOF catalysts so that high catalytic performance. However, we still have feasibility issues. To this end, we turned our attention to develop the method for facile, scalable, and efficient synthesis of Zr(IV)-based MOFs (UiO-66) with high-performance hydrolysis by imparting enriched active sites to the catalysts, as well as to examine its feasibility using the combination of UiO-66 with the organic bases including 4-ethylmorpholine (4-EM) and linear-/ branch-type polyethyleneimine (PEI). The modulated UiO-66 catalysts were synthesized by varying the total reaction concentration. The synthesized three different UiO-66 catalysts were characterized and then applied for hydrolysis rates of the methylparaoxon (MPO) nerve agent simulant. From these investigations, we found that the highest concentration led to the smallest particle size (ca. 100 nm) and highest defect density (1.8 per cluster), resulting in 3-times higher catalytic activity (0.548 s−1) in turnover frequency (TOF) relative to that of the uncontrolled UiO-66 (ca. 580 nm and 1.6 per cluster) (0.188 s−1) which is prepared by the reported procedure. In addition, the reaction process significantly influenced on the catalytic activity of UiO-66, in which the simple change of the reagent mixing method led to a ca. 182-times difference in the catalytic activity for MPO hydrolysis despite using the same reagents including catalysts and bases. Importantly, we found that the reaction process-dependent catalytic activity of UiO-66 can be significantly associated with the chelation of Zr(IV) Lewis acidic active sites by base materials of 4-EM and PEI (Lewis base). Furthermore, the solid-state catalytic system based on the polymer composite of UiO-66S/LPEI10k on the cotton fabric was also examined for MPO hydrolysis at various relative humidity and temperature conditions to create actual atmosphere conditions, which gave the possibility for actual military applications such as protective suits and equipment. In addition, we schematically demonstrated the loss of active sites on UiO-66 by chelation effects based on experimental and density functional theory (DFT)-derived computational simulation because it is highly correlated to the feasibility of Zr(IV)-based MOF catalysts for detoxification of nerve agents. In addition, we carefully propose a plausible reaction mechanism step on the nucleophilic attack by hydroxide group on the basis of the computational simulation.

Development of new hole-transport layer (HTL) materials for organic photovoltaic (OPV) applications is one crucial issue to mitigate such limitations of low power efficiency, processibility, and stability derived from poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a common HTL material. To this end, poly(3-hexylthiophene) (P3HT)-based diblock copolymers including the different ratios between polystyrene (PSty) or/and poly(neopentyl styrene sulfonate) (PNSS) as a second block segment were designed and then used for incorporating with single wall carbon nanotubes (SWCNTs) to form potentially self-dopable nanocomposites. The structure of fabricated P3HT-based diblock copolymer/SWCNT nanocomposites was examined by microscopic and spectroscopic characterizations, exhibiting a charge transfer behavior between P3HT and SWCNT, and growth of the P3HT crystalline phase along the SWCNT surface with a form of the conducting path. The acquired SWCNT nanocomposites exhibited good solubility and dispersion in various organic solvents including toluene, chlorobenzene, THF, chloroform, and DMF, which are good solvents for the PSty or/and PNSS neutral second block. The concept for the neutralized second block by protecting groups can prevent the poisoning ITO substrate by water contamination as shown in the conventional aqueous PEDOT-PSS solution. Notably, the PNSS constituent in the nanocomposite was merely acidified to give in-situ sulfonic acid groups in PSty by simple thermolysis process at 160 °C for 30 min after a solution process for fabrication of a thin film. The thermolysis step provided efficient doping of P3HT by PSS, in which the thiophene groups worked as Bronsted base are protonated by taking protons from sulfonic acid groups and then lead to a form of ionic bonds between cationic thiophene and anionic sulfonate groups. In addition, the formed ionic bonds in the nanocomposites led to an insoluble thin film, which has a good advantage for the further solvent process without substantial damages. The beneficial features of the conducting path along SWCNT and the efficient doping of P3HT by PSS in the acquired nanocomposites led to ca. 5-fold higher electrical conductivity (3.16 S cm−1) and similar work function (5.1 eV) in comparison to water contained commercial PEDOT:PSS (0.6 S cm−1 and 5.0 eV, respectively). As such, the rationally designed potentially self-dopable SWCNT nanocomposites can be one of the promising alternatives beyond the commercial PEDOT: PSS HTL material.

As many people live in cities that lack green space, biodiversity in such areas is decreasing. Suwon, the study site, a city that strives to improve its biodiversity, is close to the capital city of the Republic of Korea (ROK), and has a large population. This study aims to identify habitat-suitable areas using the longitudinal distribution model in Suwon-si, examine habitat changes when rooftop greening scenarios are applied to various use areas, and distinguish efficient use areas to expand the number of forms. To establish a rooftop greening creation scenario, the area was calculated based on the rooftop greening promotion plan in the metropolitan area, and a representative use area where rooftop greening can be applied was selected. To generate a scenario for creating rooftop greening, the property of the green area was assigned to the corresponding use area, and it was produced as an environmental variable, while the species distribution model was driven. As a result of the study, the area of increase in habitat area according to the rooftop greening for each usage area was derived, and the efficiency of the increase in habitat area compared to the rooftop greening area for each usage area was derived. To improve biodiversity in Suwon-si, rooftop greening in residential areas was found to be the most efficient, and rooftop greening efficiency in commercial areas was the lowest. It is expected that information on the increase and efficiency of the habitat of the wild birds due to rooftop greening by area of use derived from this study will help establish a rooftop greening plan and support decision-making to promote biodiversity in the city.

The carbon fiber reinforced plastics (CFRP) are still limited the used in the automotive industry mainly by the weak interfacial adhesion between the fiber and polymer matrix. Herein, to improve interfacial interactions between the carbon fiber (CF) and polypropylene (PP) matrix, poly(dimethylaminoethyl methacrylate)-b-poly(methyl methacrylate) (PDMAEMA-b-PMMA, PDM) compatibilizers are applied to functionalize the CF surface through a covalent bonding with epoxide groups on the chemically modified CF surface with tertiary amines in the PDMAEMA block, which induced intermolecular entanglement with PP chains with the PMD compatibilizers. The acquired compatibilizer-functionalized CF (CECF) was applied to fabricate PP composites by a melt-mixing method. The highly improved interfacial adhesion between the CECF and PP was confirmed by evaluating thermal, morphological, rheological, and mechanical properties. Based on the significantly enhanced interfacial adhesion, notably, the tensile strength and modulus of the CECF/PP composite exhibited a massive increase by ca. 312% and 664%, respectively, relative to those of the PP resin. The Ashby plot facilitated understanding that the acquired mechanical properties of the CECF/PP composite showed a relatively ideal position compared to reported PP composites and centered on the commercially available region in automotive components.

Herein, environmentally benign chitin nanofiber (ChNF) membranes were fabricated by regulating suspension behavior. The introduction of zeolitic imidazole frameworks (ZIF-8) into the composite membranes led to the domain formation of ChNF derived by coordinative interaction, resulting in pore size-tunable membranes. Based on the rheological, morphological, and structural characterizations, the driving force of pore-size control was studied in the aqueous suspension of ChNF and ZIF-8 according to the relative concentration. At critical concentration, the 30-ChNF membrane presents superior water permeance (40 LMH h−1) while maintaining a high rejection rate (>80% for all organic dyes). Moreover, the molecular size cut-off of the composite membranes for dyes can be controlled in the range of less than 1 nm to 2 nm. The experimental results provide a simple strategy for the preparation of pore tunable ChNF membranes using MOF with high mechanical strength, good durability, high flux, dye rejection, and antifouling ability.

Palladium nanoparticles on ionic polymer-doped graphene (Pd–IPG) nanocomposite catalysts have been investigated for efficient Suzuki coupling reactions. This combination effected highly accelerated Suzuki coupling reactions due to several advantageous features associated with the flanking ionic polymer part of the catalyst system. These include a high level of Pd incorporation, excellent dispersion stability, and increased accessibility and diffusion of the substrates onto the surface of Pd NPs. The enhanced availability of the Pd catalyst to the reacting substrates is believed to allow for ca. 16-fold higher catalytic activity than that of Pd–graphene without the ionic polymer. Moreover, high recycling capability of the catalyst (10 times) in combination with excellent product yields (>96%) and no significant leaching of the catalyst upon hot-filtration test suggest that the Pd–IPG nanocomposite catalysts have high reusability with significant retention (>95%) of the Pd species.

We present a new strategy to strongly and effectively immobilize silver nanoparticles (AgNPs) on polyamide thin film composite membranes to endow antibacterial activity. This method relies on the immobilization of relatively large silica particles (SiO 2 , ~400 nm in diameter), where AgNPs of ~30 nm in diameter are tightly and densely bound (AgNP@SiO 2 ), on the membrane surface using cysteamine as a covalent linker. The formation of multiple Ag–S chemical bonds between a “bumpy” AgNP@SiO 2 and the rough membrane surface provides a great leaching stability of AgNPs and AgNP@SiO 2 . AgNP@SiO 2 particles were well distributed over the entire membrane surface without severe aggregation. The surface coverage of the membrane by AgNP@SiO 2 was tuned by adjusting the deposition time and AgNP@SiO 2 particle concentration. The AgNP@SiO 2 -immobilized membrane showed excellent antibacterial properties against Escherichia coli , Pseudomonas aeruginosa and Staphylococcus aureus, even with a relatively low particle coverage. Importantly, the separation performance (water flux and salt rejection) of the membrane was not impaired by particle immobilization. These beneficial effects are attributed mainly to the sparse and good distribution of AgNP@SiO 2 , which can reinforce the antibacterial activity of AgNPs while having a negligible impact on the hydraulic resistance.

A novel inorganic–organic hybrid crosslinker was prepared through synthesis of a fully condensed, high molecular weight ladder-like poly(methacryloxypropyl)silsesquioxane (LPMASQ) in one pot with a facile, base-catalysed system. The fully condensed LPMASQ revealed good thermal (∼380 °C) and electrochemical stability (∼5.0 V) due to the absence of uncondensed silanol groups. LPMASQ also revealed good solubility in various organic solvents and fully gelated 1 M LiPF6 in ethyl carbonate–diethyl carbonate (EC–DEC, 3/7, v/v) electrolyte solution through fast thermal and photocuring even at a very low concentration of 2 wt%. These observations were attributed to the polymeric nature of LPMASQ containing over one hundred methacryl moieties on the rigid double-stranded siloxane backbone. To the best of our knowledge, formation of a gel polymer electrolyte with 2 wt% gelator is the smallest gelation concentration that has ever been reported. This leads to high ionic conductivity (∼6.0 mS cm−1), excellent Coulombic efficiency and battery cell performance, comparable with those of the neat liquid electrolyte. The small crosslinker content, thermal and electrochemical stability, fast thermal and photocuring and facile processing of the LPMASQ based GPEs, as well as excellent Li battery cell performances strongly hold great promise for future industrial battery applications.

Well-defined multi-armed P3HT star polymers with a gold nanoparticle (NP) core were synthesized by an arm-first method based on a ligand exchange reaction between linear end-functionalized P3HT (P3HT-SH) and gold NPs. A high loading amount of gold NPs to P3HT-SH with a relatively lower molecular weight gave a higher yield of star polymers (∼70%) with a high molecular weight (Mw = 2867k, PDI = 2.1), and the number of P3HT arm chains on one gold NP was 119. The P3HT star polymer with a gold NP core was well-dispersed both in solution and in solid, which was interestingly not crystalline because of the unique 3-dimenstional structure. In addition, surface plasmon resonance (SPR) absorption from the gold NP, as the core of the star polymer, was more enhanced both in solution and in solid, in comparison to those with non end-functionalized P3HT arm chains (P3HT-allyl); however, PL emission was more diminished because of the molecularly contacted P3HT arm chain and gold NP core. This was then introduced in an active layer consisting of P3HT:PCBM in an organic solar cell to increase optical absorption by the SPR effect from the gold NP, however, the device efficiency was rather decreased compared to that of the reference device without gold NPs, which was probably due to direct electron transfer between the gold NP and P3HT.

Polysilsesquioxanes (PSSQs) are composite materials consisting of inorganic framework and organic functional groups. Their inherent dual characteristics offer various applications including microelectronics, optics and biosciences. For the first time, free standing ladder-like PSSQ films were successfully prepared for gas separations, allowing practical applications in the membrane area. In order to fabricate a free-standing PSSQ film, a novel ladder-like poly(phenyl-co-glycidoxypropyl) silsesquioxanes with phenyl:glycidoxypropyl copolymer ratio of 6:4 (LPG64) were synthesized by a base-catalyzed sol–gel reaction. Moreover, the LPG64 films were thermally crosslinked with octa(aminophenyl)-T8-silsesquioxane (OAPS) with different concentrations of OAPS. Single gas (i.e. He, H2, CO2, O2, N2, and CH4) transport measurements were performed for the LPG64 as well as LPG64/OAPS composite membranes. The LPG64 membrane exhibited a relatively high CO2 permeability of 47.88 Barrer compared to other gases with CO2/N2 permselectivity of 30.5. The annealing effect on the transport results of the LPG64 membrane was negligible due to its rigid inorganic framework. Combination of our transport analysis and XRD characterization demonstrated that the addition of OAPS led to more dense chain packing, reducing permeability for all the gases tested in this work with increase in permselectivities. Especially, the LPG64/OAPS (80/20 wt/wt) membrane improved He/N2 and H2/N2 permselectivities by 98% and 80%, respectively, compared to those for neat LPG64 membranes.

A series of organic–inorganic hybrid spin-on-glass polymethylsilsesquioxanes were synthesized utilizing a cyclic siloxane precursor, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydroxyl cyclosiloxane (MT4-OH), copolymerized with methyltriethoxysilane (MTES) at various comonomer ratios. By selectively introducing this 2-D cyclic crosslinker, we were able to obtain spin-on-glass hybrimers with low dielectric constant (2.5–2.7), high nanoindentation modulus (5–10.5 GPa), with high thermal stability (>700 °C) without the use of porogens or additives. The use of the cyclic monomer MT4-OH greatly increased the mechanical properties, which allowed for impeccable reliability of a variety of patterns obtained through etching and chemical mechanical planarization processes, while maintaining optimal gap-filling properties. Due to the superior dielectric, mechanical, and integrated processing of these materials, these hybrids derived from MT4-OH may be utilized as next generation spin-on-glass low-dielectric constant materials.

A series of epoxy-functionalized inorganic–organic hybrid ladder-like structured polysilsesquioxanes were synthesized in one-batch via a base-catalyzed co-solvent system. Two types of epoxy functionalities were examined: aliphatic and cycloaliphatic. Obtained polymeric epoxy-functionalized ladder-like polysilsesquioxanes were cationically photopolymerized under UV irradiation over glass and plastic substrates. Obtained cross-linked films were examined as hardcoating materials as their thermal, optical, mechanical, and barrier properties were studied. These materials showed superior thermal properties (Td > 400 °C), high optical transparency (>95%), high pencil hardness (4H–9H), low dielectric constant (3.0–3.6), and good barrier properties (WVTR < 101 g m−2 day−1, OTR < 102 g m−2 day−1).

A composite membrane of silica (SiO2)/sulfonated poly (ether ether ketone) (SPEEK) nanofiber mat impregnated with Nafion was fabricated and evaluated for its potential use as a proton conductor for high temperature polymer electrolyte membrane fuel cells. The supporting SiO2/SPEEK composite nanofibrous skeleton was prepared via electrospinning of a mixture of SPEEK solution and silica sol prepared from tetraethyl orthosilicate (TEOS). The control of hydrolysis and condensation of TEOS enabled to form entangled SiO2 networks miscible to SPEEK solution. The prepared SiO2/SPEEK nanofiber mat was impregnated with Nafion® to completely fill the inter-fiber voids to prepare a dense membrane. The morphology of the nanofiber mat and the composite membrane were observed by scanning electron microscopy and the presence of SiO2 and SPEEK in the prepared nanofibers was confirmed by FTIR spectroscopy. Proton conductivity and swelling of the membrane were measured. The H2/O2 single cell test using the composite membrane as a PEM was performed. At a high temperature and low humidity condition (120 °C and 40 % RH), the maximum power density was 170 mW/cm2 for the Nafion-impregnated SiO2/SPEEK (40/60 w/w) composite nanofiber membrane that was 2.4 times higher than recast Nafion (71 mW/cm2) while SPEEK film failed.

This study investigated the photocatalytic degradation of chlorophenols using two different types of porphyrin core star block copolymers (P-PSD and P-PD) with irradiation using visible light. Both P-PSD and P-PD catalysts show similar tendencies in the degradation of chlorophenols. Pentachlorophenol degraded faster than other chlorinated phenols (pentachlorophenol > 2,4,6-trichlorophenol > 2,4-dichlorophenol). The removal rate of chlorophenols using P-PSD was higher than the removal rate using P-PD, a difference which could be attributed to the hydrophobicity of P-PSD. The degradation intermediates and by-products of the chlorophenols were also identified. The analysis results revealed that the degradation of highly-chlorinated phenols was more rapid than the degradation of the less-chlorinated phenols, as confirmed by residual chlorinated compound and chloride ions that were released. The newly synthesized P-PSD catalyst is non-toxic to bacteria. For these reasons, the process of photocatalytic degradation using porphyrin core star block copolymers has potential advantages for the degradation of dissolved chlorophenol pollutants in water.

The stereo cyclic siloxane compounds having tetra hydroxyl and tetra methyl group were synthesized by hydrolysis of tetrahydrido tetramethyl cyclosiloxane consisting of four stereoisomers. Among the stereo cyclic isomers, cis-trans-cis tetrahydroxyl tetramethyl cyclosiloxane (2) was separated by recrystallization and was used as a monomer species for preparation of ladder-like polymethylsilsesquioxane (PMSQ). The isolated isomer was directly polymerized in THF with potassium carbonate (K2CO3) by systematic ring condensation. The hydrolyzed stereoisomers were characterized by 1H and 29Si NMR, and HPLC. The structure of the synthesized PMSQs were characterized by size exclusion chromatography (SEC), MALDI-TOF mass, 29Si NMR, and small angle X-ray scattering (SAXS).

In this study, new polymeric adsorbents, 2 types of polystyrene-block-poly (N-isopropylacrylamide) (PSN, structure of hydrophobic core and hydrophilic shell), were developed and applied for removal of organic pollutants from wastewater. Encapsulation of organic pollutants by the polystyrene-block-poly (N-isopropylacrylamide) (PSN) resulted in increasing hydrophobicity of the polystyrene with abundant hydrophobic spaces within the amphiphilic block copolymer. The encapsulation mechanism of BTEX by PSN was investigated and found to be mainly attributable to the Van der Waals interactions between the aromatic ring of BTEX and the hydrophobic core of PSN. Polystyrene-block-poly (N-isopropylacrylamide) showed good potential as a novel and cost effective adsorbent for application to wastewater treatment, which can be simply regenerated and reused using an external temperature changing system.

Over the past half century, low dielectric materials have been intensively researched by ceramic and polymer scientists. However, these materials possess a vast myriad of electrical, thermal, chemical, and mechanical properties that are just as crucial as the name that classifies them. Therefore, in many cases, the applications of low dielectric constant materials are dictated by these other properties, and the choice of low dielectric material may have a tremendous effect on a device’s performance and lifetime.

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Photo and temperature cured polymer dielectrics could be fabricated on a gate-patterned glass, with two immiscible polymer precursors, divinyltetramethyldisiloxane-bis(benzocyclobutene) (BCB precursor) and poly(melamine-co-formaldehyde)acrylate (PMFA), which have excellent insulating properties, but show discernible dielectric constants and polarities. On hydrophobic BCB-assisted PMFA blend dielectrics (approximately 400 nm thick), organic field-effect transistors (OFET) and complementary inverters were demonstrated using pentacene and N,N′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) as semiconducting channels. The values of field-effect mobilities showed up to 0.33 cm2 V−1 s−1 (for pentacene) and 0.85 cm2 V−1 s−1 (for PTCDI-C13), respectively. In addition, these based complementary inverter was successfully demonstrated with a high voltage gain of ca. 41, specifically, onto the 10 wt% BCB-assisted PMFA dielectric optimized to achieve a hydrophobic and smooth surface by vertically phase-separating the immiscible polymers.

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