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Surface-compartmentalized micellar nanostructures (Janus and patchy micelles) have gained increasing interest due to their unique properties opening highly relevant applications, e.g., as efficient particulate surfactants, compatibilizers in polymer blends, or templates for catalytically active nanoparticles. We present a facile method for the production of worm-like Janus micelles based on crystallization-driven self-assembly of a double-crystalline triblock terpolymer with a crystallizable polyethylene middle block and two highly incompatible corona blocks, polystyrene and poly(ethylene oxide). This approach enables the production of amphiphilic Janus micelles with excellent interfacial activity by a comparably simple heating and cooling protocol directly in solution.

Combining the unique corona structure of worm‐like patchy micelles immobilized on a polymer fiber with the molecular self‐assembly of 1,3,5‐benzenetricarboxamides (BTAs) leads to hierarchical superstructures with a fir‐tree‐like morphology. For this purpose, worm‐like patchy micelles bearing pendant, functional tertiary amino groups in one of the corona patches were prepared by crystallization‐driven self‐assembly and immobilized on a supporting polystyrene fiber by coaxial electrospinning. The obtained patchy fibers were then immersed in an aqueous solution of a tertiary amino‐functionalized BTA to induce patch‐mediated molecular self‐assembly to well‐defined fir‐tree‐like superstructures upon solvent evaporation. Interestingly, defined superstructures are obtained only if the pendant functional groups in the surface patches match with the peripheral substituents of the BTA, which is attributed to a local increase in BTA concentration at the polymer fibers’ surface., Hierarchical fir‐tree‐like superstructures are accessible by utilizing the unique corona structure of patchy worm‐like micelles immobilized on electrospun polymer fibers and the molecular self‐assembly of a 1,3,5‐benzenetricarboxamide. The used combination of crystallization‐driven and molecular self‐assembly concepts can give access to a large variety of fibrillar superstructures with potential applications in filtration or catalysis.

A process for preparing active, strong base and acid self-standing individual membranes and printed structures is established by electrospinning and two-dimensional (2D) printing of the correspondi...

Surface-modified carbon nanotubes (CNTs) have become well-established filler materials for polymer nanocomposites. However, in immiscible polymer blends, the CNT-coating is selective toward the more compatible phase, which suppresses their homogeneous distribution and limits harnessing the full potential of the filler. In this study, we show that multiwalled CNTs with a patchy polystyrene/poly(methyl methacrylate) (PS/PMMA) corona disperse equally well in both phases of an incompatible PS/PMMA polymer blend. Unlike polymer-grafted CNTs with a uniform corona, the patchy CNTs are able to adjust their corona structure to the blend phases by selective swelling/collapse of respective miscible/immiscible surface patches. Importantly, the high interfacial activity of patchy CNTs further causes a significant decrease in PMMA droplet size with increasing filler content. The combined effect of compatibilization and homogeneous distribution makes patchy CNTs interesting materials for polymer blend nanocomposites, where next to the compatibilization, a homogeneous filler distribution is important to gain the desired materials property (e.g., reinforcement).

Self-assembly of block copolymers (BCPs) in three-dimensional (3D) confinement of emulsion droplets has emerged as a versatile route for the formation of functional micro- and nanoparticles. While the self-assembly of amorphous coil-coil BCPs is fairly well documented, less is known about the behavior of crystalline-coil BCPs. Here, we demonstrate that confining a linear ABC triblock terpolymer with a crystallizable middle block in oil-in-water (O/W) emulsions results in a range of microparticles with frustrated inner structure originating from the conflict between crystallization and curved interfaces. Polystyrene-block-polyethylene-block-poly(methyl methacrylate) (PS-b-PE-b-PMMA, S32E36M3293) in toluene droplets was subjected to different preparation protocols. If evaporation was performed well above the bulk crystallization temperature of the PE block (Tevap > Tc), S32E36M3293 first microphase-separated into microparticles with lamella morphology followed by crystallization into a variety of frustrated morphologies (e.g., bud-like, double staircase, spherocone). By evaporating at significantly lower temperatures that allow the PE block to crystallize from solution (Tevap < Tc), S32E36M3293 underwent crystallization-driven self-assembly into patchy crystalline-core micelles, followed by confinement assembly into lenticular microparticles with compartmentalized hexagonal cylinder lattices. The frequency of these frustrated morphologies depends on polymer concentration and the evaporation protocol. These results provide a preliminary understanding of the morphological behavior of semicrystalline block copolymers in 3D soft confinement and may provide alternative routes to structure multicompartment microparticles from a broader range of polymer properties.

Cationic cylindrical polymer brushes based on polybutadiene-block-poly(2-vinylpyridine) were applied as structure-directing agent for mesostructuring Fe2O3 nanoparticles into nanotubes. After temperature-controlled template removal, the obtained non-woven catalysts were tested for the photodegradation of ciprofloxacin under terrestrial solar radiation. At a slightly basic pH value, as typically encountered in clinical wastewaters, the mesostructured Fe2O3 shows a 4.5 times faster degradation of ciprofloxacin than commercial Aeroxide® TiO2 P25. Even wide-bandgap ZnO, mesostructured in the same way, is 1.6 times slower. Moreover, the non-woven-like structure of the catalyst allows for easy recovery of the catalyst and operation in a continuous flow reactor. Graphical abstract Electronic supplementary material The online version of this article (10.1007/s11356-020-10899-6) contains supplementary material, which is available to authorized users.

The formation and rheological properties of hydrogels based on amphiphilic ABA triblock polyether copolymers are described, relying solely on the hydrophobic interaction of long-chain alkyl glycidyl ether (AlkGE)- based A-blocks that are combined with a hydrophilic poly(ethylene glycol) (PEG) midblock. Via anionic ring-opening copolymerization (AROP), ethylene oxide (EO) and long-chain alkyl glycidyl ethers (AlkGEs) were copolymerized, using deprotonated poly(ethylene glycol) (PEG) macroinitiators (Mn of 10, 20 kg mol-1). The polymerization afforded amphiphilic ABA triblock copolymers with molar masses in the range of 21-32 kg mol-1 and dispersities (Đ) of Đ = 1.07-1.17. Kinetic studies revealed random copolymerization of EO and AlkGE, indicating random spacing of the hydrophobic AlkGE units by polar EO units. Following this approach, the hydrophobicity of the apolar blocks of amphiphilic ABA triblock polyethers can be tailored. Detailed rheological measurements confirmed the successful formation of hydrogels at different pH values as a consequence of nonpolar interactions and alkyl chain crystallization. Hydrogel formation was also observed at different ionic strengths (i.e., varied salt concentration), based on the hydrophobic aggregates. This behavior is in contrast to other often-used supramolecular cross-linking strategies, such as Coulomb interactions, complexation, or hydrogen bonding. Micro-differential scanning calorimetry (μ-DSC) measurements of the hydrogels revealed crystalline hydrophobic domains with melting temperatures in the physiological temperature range. In 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide (MTT) assays, diblock copolymers possessing structural analogy to the triblock copolymers were studied to assess the general cytotoxicity of amphiphilic polyethers bearing long alkyl chains at the polyether backbone, using splenic immune cells. At intermediate polymer concentrations, no cytotoxic effects were observed. This indicates that long-chain alkyl glycidyl ethers are promising for the introduction of highly hydrophobic as well as crystalline motifs at the polyether backbone in hydrogels for biomedical purposes.

Multiresponsive polymers that can respond to several external stimuli are promising materials for a manifold of applications. Herein, a facile method for the synthesis of triple‐responsive (pH, temperature, CO2) poly(N,N‐diethylaminoethyl methacrylamide) by a post‐polymerization amidation of poly(methyl methacrylate) (PMMA) is presented. Combined with trivalent counterions ([Fe(CN)6]3−) both an upper and lower critical solution temperature (UCST/LCST)‐type phase behavior can be realized at pH 8 and 9. PMMA and PMMA‐based block copolymers are readily accessible by living anionic and controlled radical polymerization techniques, which opens access to various responsive polymer architectures based on the developed functionalization method. This method can also be applied on melt‐processed bulk PMMA samples to introduce functional, responsive moieties at the PMMA surface., Making PMMA responsive: PMMA can be converted into a triple‐responsive polymer, being responsive to temperature, pH and CO2 gas, by a quantitative post‐polymerization amidation with N,N‐diethylethylenediamine. This will open access to a large variety of responsive macromolecular architectures, because this method can be applied to PMMA and PMMA‐based block copolymers, being easily accessible by living anionic or controlled radical polymerization (see scheme).

Poly(limonene carbonate) (PLimC) has a huge potential as a sustainable biobased polymer due to its promising property profile and the availability of the raw materials from nonedible resources, i.e...

Nanoparticles immobilized on protective polymer supports are highly attractive for various applications in industrial processes. However, nanoparticles tend to agglomerate during the preparation of...

Functional, hierarchically mesostructured nonwovens are of fundamental importance because complex fiber morphologies increase the active surface area and functionality allowing for the effective immobilization of metal nanoparticles. Such complex functional fiber morphologies clearly widen the property profile and enable the preparation of more efficient and selective filter media. Here, we demonstrate the realization of hierarchically mesostructured nonwovens with barbed wire-like morphology by combining electrospun polystyrene fibers, decorated with patchy worm-like micelles, with solution-processed supramolecular short fibers composed of 1,3,5-benzenetricarboxamides with peripheral N,N-diisopropylaminoethyl substituents. The worm-like micelles with a patchy microphase-separated corona were prepared by crystallization-driven self-assembly of a polyethylene based triblock terpolymer and deposited on top of the polystyrene fibers by coaxial electrospinning. The micelles were designed in a way that their patches promote the directed self-assembly of the 1,3,5-benzenetricarboxamide and the fixation of the supramolecular nanofibers on the supporting polystyrene fibers. Functionality of the mesostructured nonwoven is provided by the peripheral N,N-diisopropylaminoethyl substituents of the 1,3,5-benzenetricarboxamide and proven by the effective immobilization of individual palladium nanoparticles on the supramolecular nanofibers. The preparation of hierarchically mesostructured nonwovens and their shown functionality demonstrate that such systems are attractive candidates to be used for example in filtration, selective separation and heterogenous catalysis.

Responsive fluorescent materials offer a high potential for sensing and (bio-)imaging applications. To investigate new concepts for such materials and to broaden their applicability, the previously reported non-fluorescent zinc(II) complex [Zn(L)] that shows coordination-induced turn-on emission was encapsulated into a family of non-fluorescent polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer micelles leading to brightly emissive materials. Coordination-induced turn-on emission upon incorporation and ligation of the [Zn(L)] in the P4VP core outperform parent [Zn(L)] in pyridine solution with respect to lifetimes, quantum yields, and temperature resistance. The quantum yield can be easily tuned by tailoring the selectivity of the employed solvent or solvent mixture and, thus, the tendency of the PS-b-P4VP diblock copolymers to self-assemble into micelles. A medium-dependent off-on sensor upon micelle formation could be established by suppression of non-micelle-borne emission background pertinent to chloroform through controlled acidification indicating an additional pH-dependent process.

Air emissions, atmospheric transport and subsequent deposition of microplastics to other environments are now recognized. However, atmospheric dry and wet deposition of plastic particles and how different weather conditions may affect this fallout process are still poorly investigated. Hence, we examined wet and dry deposition of airborne plastic particulates from the atmosphere at a site in Kassel in Central Germany. Monthly samples of wet and dry deposition were taken separately over one year (05/2019-05/2020) and analysed by micro-Fourier-Transform Infrared spectroscopy (µFTIR) down to 11 µm. Additionally, one exemplary dry deposition sample was subjected to Raman analyses to investigate the abundance of dry deposited plastic particles in the lower micron and submicron size range. Microplastic particles in size range of 11 µm to 130 µm were detected in all wet deposition samples and in 5 out of 12 dry deposition samples by µFTIR. Polypropylene particles were found most frequently and accounted for 62% and 54% of all particles in wet and dry deposition, respectively. Wet deposition of plastics dominated at the study site and comprised 62% of the total number and 70% of the total mass of deposition. Plastic wet deposition fluxes (DFs) were 10 ± 5 MPs m− 2 day− 1 and accounted for 4284 MPs m− 2 a− 1. Microplastic deposition was elevated when the dominant wind direction was recorded in the direction from the city centre of Kassel and concentrations in precipitation correlated significantly with population-weighted air mass trajectories. Thus, anthropogenic activities contribute to the MP pollution at the study site. Raman analyses revealed additional plastic particles in the micron (> 10 µm) and lower micron (between 10 µm and 1 µm) range but submicron (

The combination of polymers with nanoparticles offers the possibility to obtain customizable composite materials with additional properties such as sensing or bistability provided by a switchable spin crossover (SCO) core. For all applications, a precise control over size and shape of the nanomaterial is highly important as it will significantly influence its final properties. By confined synthesis of iron(II) SCO coordination polymers within the P4VP cores of polystyrene-block-poly-4-vinylpyridine (PS-b-P4VP) micelles in THF we are able to control the size and also the shape of the resulting SCO nanocomposite particles by the composition of the PS-b-P4VP diblock copolymers (dBCPs) and the amount of complex employed. For the nanocomposite samples with the highest P4VP content, a morphological transition from spherical nanoparticle to worm-like structures was observed with increasing coordination polymer content, which can be explained with the impact of complex coordination on the self-assembly of the dBCP. Furthermore, the SCO nanocomposites showed transition temperatures of T1/2 = 217 K, up to 27 K wide hysteresis loops and a decrease of the residual high-spin fraction down to γHS = 14% in the worm-like structures, as determined by magnetic susceptibility measurements and Mössbauer spectroscopy. Thus, SCO properties close or even better (hysteresis) to those of the bulk material can be obtained and furthermore tuned through size and shape control realized by tailoring the block length ratio of the PS-b-P4VP dBCPs.

Electrospinning is a simple, low cost, and high throughput technique that allows for processing of polymers into fibers. The process can be controlled to allow access for well-defined continuous fibers that are of interest for a wide range of applications including as tissue scaffolds, as nanowires in optoelectronic devices, and in catalysis. Conventional electrospinning processes use polymer solutions with high molecular weights. Here, we report the electrospinning of one-dimensional (1D) fiber-like block copolymer micelles containing a crystalline core. We successfully accessed core-shell microfibers in which 1D micelles containing a crystalline poly(ferrocenyldimethylsilane) (PFS) core are immobilized on a polystyrene microfiber via coaxial electrospinning. Furthermore, we describe efforts to extend this approach to the use of 1D micelles comprising of a crystalline, π-conjugated poly(di-n-hexylfluorene) (PDHF) core. Electrospinning was also successfully used to prepare microfibers consisting solely of 1D micelles with a PFS crystalline core, the first examples where a template material is not required.

When suspensions are exposed to shear forces, the particles may form ordered structures depending on their shapes, concentrations, and the material. For some processes, e.g., for wet-film coating, it is important to know how fast these structures form in shear fields and for how long the structures persist when the shear is relaxed. To obtain information on the particle structure formation and the decay time, the effective viscosity of nematic suspensions of Na-hectorite nanosheets was investigated by rheology employing a cone-plate measurement geometry. The necessary time for the formation textured nematic films could be deduced by carrying out effective viscosity measurements at constant time steps. Information could also be obtained on the lifetime of the platelet textures when shear is relaxed. All this information was employed to identify geometrical requirements for slot dies to produce barrier liners with nanosheet layers oriented parallel to PET substrates. Thereby, we obtained green and simple coatings that are in line with state-of-the-art high-performance materials such as metalized plastic foils in terms of oxygen barrier properties.

The confinement assembly of block copolymers shows great potential regarding the formation of functional microparticles with compartmentalized structure. Although a large variety of block chemistries have already been used, less is known about microdomain degradation, which could lead to mesoporous microparticles with particularly complex morphologies for ABC triblock terpolymers. Here, we report on the formation of triblock terpolymer-based, multicompartment microparticles (MMs) and the selective degradation of domains into mesoporous microparticles. A series of polystyrene-block-polybutadiene-block-poly(L-lactide) (PS-b-PB-b-PLLA, SBL) triblock terpolymers was synthesized by a combination of anionic vinyl and ring-opening polymerization, which were transformed into microparticles through evaporation-induced confinement assembly. Despite different block compositions and the presence of a crystallizable PLLA block, we mainly identified hexagonally packed cylinders with a PLLA core and PB shell embedded in a PS matrix. Emulsions were prepared with Shirasu Porous Glass (SPG) membranes leading to a narrow size distribution of the microparticles and control of the average particle diameter, d ≈ 0.4 µm–1.8 µm. The core–shell cylinders lie parallel to the surface for particle diameters d < 0.5 µm and progressively more perpendicular for larger particles d > 0.8 µm as verified with scanning and transmission electron microscopy and particle cross-sections. Finally, the selective degradation of the PLLA cylinders under basic conditions resulted in mesoporous microparticles with a pronounced surface roughness.

Acrylonitrile–butadiene–styrene (ABS) is a commercial polymer for widely industrial applications due to its good mechanical and physical properties. However, there are only countable reports regarding its fibers from electrospinning. Comprehensive investigation on its optimized electrospinning parameters is missing. Herein, ABS fibers with different fiber diameters were produced by electrospinning. The electrospinning conditions, including the solvents, solution concentrations and amounts of different salt additives, have been comprehensively investigated. The morphologies of electrospun ABS fibers are studied by scanning electron microscopy and Raman spectroscopy. Different fiber diameters and coating densities are applied for filtration applications, which showed excellent filtration performance. The filtration efficiency of up to 99%, low pressure drop of

In this work, we provide a detailed study on the influence of patch size and chemistry on the catalytic activity of patchy hybrid nonwovens in the gold nanoparticle (Au NP) catalysed alcoholysis of dimethylphenylsilane in n-butanol. The nonwovens were produced by coaxial electrospinning, employing a polystyrene solution as the core and a dispersion of spherical or worm-like patchy micelles with functional, amino group-bearing patches (dimethyl and diisopropyl amino groups as anchor groups for Au NP) as the shell. Subsequent loading by dipping into a dispersion of preformed Au NPs yields the patchy hybrid nonwovens. In terms of NP stabilization, i.e., preventing agglomeration, worm-like micelles with poly(N,N-dimethylaminoethyl methacrylamide) (PDMA) patches are most efficient. Kinetic studies employing an extended 1(st) order kinetics model, which includes the observed induction periods, revealed a strong dependence on the accessibility of the Au NPs' surface to the reactants. The accessibility is controlled by the swellability of the functional patches in n-butanol, which depends on both patch chemistry and size. As a result, significantly longer induction (t(ind)) and reaction (t(R)) times were observed for the 1(st) catalysis cycles in comparison to the 10(th) cycles and nonwovens with more polar PDMA patches show a significantly lower t(R) in the 1(st) catalysis cycle. Thus, the unique patchy surface structure allows tailoring the properties of this "tea-bag"-like catalyst system in terms of NP stabilization and catalytic performance, which resulted in a significant reduction of t(R) to about 4 h for an optimized system.

Microplastic that was exposed to the environment is much more likely internalized by cells than pure unmodified microplastic., Microplastic particles ubiquitously found in the environment are ingested by a huge variety of organisms. Subsequently, microplastic particles can translocate from the gastrointestinal tract into the tissues likely by cellular internalization. The reason for cellular internalization is unknown, since this has only been shown for specifically surface-functionalized particles. We show that environmentally exposed microplastic particles were internalized significantly more often than pristine microplastic particles into macrophages. We identified biomolecules forming an eco-corona on the surface of microplastic particles, suggesting that environmental exposure promotes the cellular internalization of microplastics. Our findings further indicate that cellular internalization is a key route by which microplastic particles translocate into tissues, where they may cause toxicological effects that have implications for the environment and human health.

Polycarbonate diblock copolymers with a biobased poly(limonene carbonate) (PLimC) and a poly(cyclohexene carbonate) (PCHC) block were prepared via β-diiminate zinc catalysed living ring-opening copolymerization (ROCOP) of CO2 and trans-limonene oxide and cyclohexene oxide, respectively. trans-Limonene oxide can be readily obtained from limonene, a renewable non-food source, that can be found in the peel of many citrus fruits and is the main component of orange oil. The block formation was realised by sequential addition of the epoxide monomers. The composition of the resulting amorphous poly(limonene carbonate)-block-poly(cyclohexene carbonate) (PLimC-b-PCHC) diblock copolymers was analysed by 1H NMR spectroscopy. The self-assembly of the diblock copolymers into well-defined bulk morphologies was studied by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). Depending on the composition and molecular weight the formation of cylindrical, lamellar, and hexagonally perforated lamellar morphologies was observed.

This highlight summarizes current challenges of mesostructuring and focuses on the scope and the potential of the ELAN – (electrostatic attraction of nanoobjects) strategy in mesostructuring of transition metal compounds. It discusses the limitations of this concept and highlights prominent examples. ELAN exploits the Coulomb attraction between inorganic precursors and polymeric templates in order to prevent macrophase separation. Essential requirements for ELAN are tailor-made, mesoscopic polyelectrolytic templates and charged molecular oligo-ions or stable colloids carrying a surface charge. The ELAN-strategy is highly reliable and opens the way to crystalline, mesoporous transition metal compounds with predefined polymorphism. It also provides the possibility to adjust wall chemistry and reactivity as well as the flexibility to synthesise different mesostructures (spheres, non-woven arrays or hexagonally ordered phases).

Nanoparticles of the 1D and 2D coordination polymers [Zn(OAc)2(bipy)]n and [Zn(TFA)2(bppa)2]n were prepared, employing polystyrene-block-poly(4-vinylpyridine) diblock copolymers with different weight fractions of the 4-vinylpyridine (4VP) block and comparable overall molecular weights of Mn ≈ 155 kg mol−1 as template (SV-15 and SV-42 with 15 and 42 wt% 4VP, respectively). [Zn(OAc)2(bipy)]n nanoparticles were successfully synthesised within the 4VP core of SV-42 micelles, showing a core size of Dcore = 47 ± 5 nm and a hydrodynamic diameter of Dh = 157 ± 46 nm, determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The crystallinity of the composite is quite low, showing only low intensity reflexes in the powder X-ray diffraction (PXRD) pattern with the highest particle load. No indications for larger microcrystals were detected by scanning electron microscopy (SEM), proving the successful integration of the coordination polymer nanoparticles within the micellar cores. Nanocomposites of the 2D coordination network [Zn(TFA)2(bppa)2]n were synthesised using both diblock copolymers. The particle core sizes (from TEM) and hydrodynamic diameters (from DLS) correlate with the 4VP fraction of the micelles, resulting in Dcore = 46 ± 6 nm for SV-42 and 15 ± 2 nm for SV-15 and Dh = 340 ± 153 nm and 177 ± 57 nm, respectively. The successful synthesis was proven by PXRD and SEM images, confirming the absence of larger crystallites. Hence, it is possible to synthesise nanocomposites of Zn-based 1D and 2D coordination polymers by a direct approach utilizing diblock copolymer micelles as template.

Block copolymers with crystallizable blocks are a highly interesting class of materials owing to their unique self-assembly behaviour both in bulk and solution. This Special Issue brings together new developments in the synthesis and self-assembly of semicrystalline block copolymers and also addresses potential applications of these exciting materials.

In this study, we report a detailed spectroscopic study concerning the energy levels and vibrational structure of thiophene-pyrrole-containing S,N-heteroacenes. The aim of the study is first, to understand the differences in the photoluminescence (PL) efficiencies in this structurally similar series and second, to compare the electronic structure of S,N-heteroacenes to that of linear acenes and phenacenes, with a view to derive guidelines for the design of singlet fission materials. For S,N-heteroacenes comprising seven fused heterocyclic rings, we observe a higher PL quantum yield for derivatives with terminal thienothiophene units than for thienopyrrole-capped ones. This is assigned to a stronger tendency of the thienopyrrole-capped derivatives to form nonemissive associates in dilute solution, producing emissive excimers at higher concentration. By conducting time-resolved PL studies at 77 K, we further determine the lowest singlet and triplet energies for the S,N-heteroacenes with three, five, and seven fused rings. We show that their energies evolve with oligomer length analogously to those of phenacenes, yet in a fundamentally different way from that of linear acenes. This difference in evolution is attributed to the increasingly biradical character in acenes with increasing chain length in contrast to the S,N-heteroacenes and phenacenes.

A series of cationic diblock copolymers were synthesized via sequential anionic polymerization of 2-vinylpyridine and ethylene oxide and further quaternization of the resulting diblock copolymers with dimethyl sulfate. Diblock copolymers with a degree of polymerization (DP) of the cationic block equal to 40 and DP of the poly(ethylene oxide) (PEO) block equal to 45, 210 and 450, as well as a cationic homopolymer with DP = 40 (control), were adsorbed on the surface of anionic liposomes of 40–60 nm in diameter. The liposomes were constructed with egg lecithin admixed with 0.1 mole fraction of a doubly anionic lipid, cardiolipin. The liposome–polymer complexes were characterized using electrophoretic mobility measurements, dynamic light scattering, conductivity, fluorescence and UV spectroscopy, and differential scanning calorimetry. Adsorption of the polymers causes the liposomes to aggregate; the only exception is the diblock copolymer with DP of the PEO block of 450, which shows an aggregation-preventing effect. In all cases, the integrity of liposomes is retained upon their complexation with polymers. The diblock copolymer with a short PEO block induces clustering of anionic lipid in the outer leaflet of the membrane; this effect becomes less pronounced with increasing DP of the PEO block. The differences in behaviour of the diblock copolymers are explained in terms of copolymer cluster formation via hydrogen bonding between neighbouring PEO blocks. These observations are important for interpretation of biological effects produced by cationic polymers and selection of cationic polymers for biomedical applications. © 2017 Society of Chemical Industry

Zinc oxide (ZnO) nanoparticles were mesostructured by polybutadiene-block-poly(2-vinylpyridine) cylindrical polymer brushes as a template. Loading the positively charged vinylpyridine block with ZnO nanoparticles produced hybrid rods with high aspect ratio. Mesostructured ZnO nanotubes obtained by pyrolytic template removal show high activity in the photocatalytic degradation of ciprofloxacin using a continuous flow reactor and irradiation with terrestrial solar spectrum. In comparison with Degussa P25, a titanium dioxide photocatalyst, the degradation is 2.9 times faster. Due to its non-woven microstructure, the photocatalyst, moreover, can be easily separated from fluid reaction media by filtration.

Nanoparticles of the spin‐crossover coordination polymer [FeL(bipy)]n were synthesized by confined crystallization within the core of polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) diblock copolymer micelles. The 4VP units in the micellar core act as coordination sites for the Fe complex. In the bulk material, the spin‐crossover nanoparticles in the core are well isolated from each other allowing thermal treatment without disintegration of their structure. During annealing above the glass transition temperature of the PS block, the transition temperature is shifted gradually to higher temperatures from the as‐synthesized product (T 1/2↓=163 K and T 1/2↑=170 K) to the annealed product (T 1/2↓=203 K and T 1/2↑=217 K) along with an increase in hysteresis width from 6 K to 14 K. Thus, the spin‐crossover properties can be shifted towards the properties of the related bulk material. The stability of the nanocomposite allows further processing, such as electrospinning from solution., Spin doctor: The synthesis and characterization of spin‐crossover nanoparticles with improved spin‐crossover properties in a block‐copolymer matrix gives a spin‐crossover nanocomposite which is stable enough to allow further processing, such as electrospinning from solution.

Oxidative thermal removal of the polymeric templates is not trivial for molybdenum oxides and hampers mesostructuring of this material. At ambient oxygen fugacity, MoVI is the thermodynamically stable oxidation state and sublimation of MoO3 leads to a quick loss of the mesostructure through Oswald ripening. Taking advantage of the Boudouard equilibrium allows to fix the oxygen fugacity at a level where non-volatile MoO2−x is stable while carbonaceous material may be oxidized by CO2. Mesostructured MoO2−x can be chemically converted into MoO3 or MoN under retention of the mesostructure.

By influencing both the interfacial adhesion and the morphology, compatibilizers determine the mechanical properties of polymer blends. Here, we study the mechanical properties, in particular the fatigue crack propagation (FCP) of immiscible blends of poly(2,6-dimethyl-1,4-phenylene ether)/poly(styrene- co -acrylonitrile) (PPE/SAN), compatibilized with Janus nanoparticles (JPs) and linear polystyrene- block -polybutadiene- block -poly(methyl methacrylate) (SBM) triblock terpolymers. Synergistic effects of a mixture of both compatibilizers improve the FCP behavior and reveal the important role of interface stiffness and flexibility on the mechanical properties of polymer blends. The triblock terpolymer and JPs allow at the same time an elastic and stiff linkage at the blend interface and induce multiple deformation mechanisms such as crack bridging and matrix fibrillation that can dissipate energy and contribute to an improved FCP behavior. The presented concept allows tailoring macro-mechanical properties of immiscible polymer blends by adjusting blend morphology and interfacial properties.

Die heterogene Katalyse an tragerfixierten Nanopartikeln (NP) ist ein uberaus attraktives Forschungsfeld. Eine der grosten Herausforderungen ist jedoch weiterhin die effiziente Stabilisierung der NP ohne Einschrankung ihrer katalytischen Aktivitat. Durch eine Kombination bekannter Top-down- (koaxiales Elektrospinnen) und Bottom-up-Methoden (kristallisationsinduzierte Selbstassemblierung) ist es uns gelungen, Fasermatten mit funktionellen, nanometergrosen Kompartimenten (Patches) auf der Oberflache herzustellen. Diese Patches sind in der Lage, Gold-Nanopartikel (AuNP) selektiv zu binden und zu stabilisieren. Die mit AuNP beladenen Hybridfasermatten zeigten in der Alkoholyse von Dimethylphenylsilan bereits nach vergleichsweise kurzen Reaktionszeiten sowie unter milden Bedingungen quantitativen Umsatz. Die exzellente Wiederverwendbarkeit zeigt sich darin, dass selbst nach 10 aufeinanderfolgenden Zyklen keine Reduktion der katalytischen Aktivitat oder ein “Ausbluten” von Gold beobachtet werden konnte. Die Flexibilitat der vorgestellten Methode erlaubt eine einfache Ubertragung auf andere Tragerfasern und unterschiedliche katalytisch aktive NP, wodurch sich ein breites Anwendungsspektrum in der heterogenen Katalyse eroffnet.

One-dimensional patchy nanostructures are interesting materials due to their excellent interfacial activity and their potential use as carrier for functional nanoparticles. Up to now only wormlike crystalline-core micelles (wCCMs) with a nonfunctional patchy PS/PMMA corona were accessible using crystallization-driven self-assembly (CDSA) of polystyrene-block-polyethylene-block-poly(methyl methacrylate) (SEM) triblock terpolymers. Here, we present a facile approach toward functional, patchy wCCMs, bearing tertiary amino groups in one of the surface patches. The corona forming PMMA block of a SEM triblock terpolymer was functionalized by amidation with different N,N-dialkylethylenediamines in a polymer analogous fashion. The CDSA of the functionalized triblock terpolymers in THF was found to strongly depend on the polarity/solubility of the amidated PMMA block. The lower the polarity of the amidated PMMA block (increased solubility), the higher is the accessible degree of functionalization upon which define...

Gold nanoparticles (AuNP) with pyridyl end-capped polystyrenes (PS-4VP) as "quasi-monodentate" ligands self-assemble into ordered PS-4VP/AuNP nanostructures with 3D hexagonal spatial order in the dried solid state. The key for the formation of these ordered structures is the modulation of the ratio AuNP versus ligands, which proves the importance of ligand design and quantity for the preparation of novel ordered polymer/metal nanoparticle conjugates. Although the assemblies of PS-4VP/AuNP in dispersion lack in high dimensional order, strong plasmonic interactions are observed due to close contact of AuNP. Applying temperature as an external stimulus allows the reversible distortion of plasmonic interactions within the AuNP nanocomposite structures, which can be observed directly by naked eye. The modulation of the macroscopic optical properties accompanied by this structural distortion of plasmonic interaction opens up very interesting sensoric applications.

There are only a few non-ionic polymers known for showing thermoresponsivity of UCST-type. Copolymers of acrylamide (AAm) and acrylonitrile (AN) represent one of such thermoresponsive polymers. The present work shows pH-dependent UCST-transitions of this copolymer system. Herein, systematic studies were carried out to show hydrolytic stability and retention of UCST of the copolymer under various conditions. Regeneration of lost UCST-type transitions under extreme pH conditions could be achieved by changing pH, and by addition of electrolytes. Reversible addition fragmentation chain transfer (RAFT) was employed as a tool to synthesize copolymers of AAm and AN. Hydrolysis reactions were carried out intentionally under acidic and alkaline conditions, in order to analyze the chemical stability of the synthesized copolymers as well as to introduce carboxylic groups into the polymer structure. The obtained results showed high tolerance of poly(AAm-co-AN) samples under acidic conditions even after long periods of storage (25 days at pH 3) or after use of pH 0 and increased temperatures (40 °C). In the case of base catalyzed hydrolysis, the thermoresponsive behavior was significantly influenced during hydrolysis in buffer solution of pH 9. Loss and regeneration of the phase transition temperature of these copolymers could be achieved by changing the pH from basic to acidic. Meanwhile, hydrolysis at pH 14 at 40 °C influenced the thermoresponsive behavior and the chemical stability of the polymer, increasing the phase transition temperature over 30 °C. Further, we observed that additives, e.g. formamide can act as a sacrificial agent for providing stable UCST-type transitions even under alkaline conditions as well as at high temperatures (85 °C).

The effect of compatibilization with a symmetrical polystyrene- block -polybutadiene- block -poly(methyl methacrylate) (SBM) triblock terpolymer on the morphological and mechanical properties (specifically toughness) of immiscible poly(2,6-dimethyl-1,4-phenylene ether)/poly(styrene- co -acrylonitrile) (PPE/SAN) blends with different blend (w/w) ratios is investigated. We study the effect of blend viscosity on the localization of the compatibilizer at the blend interface, influencing the mechanical properties of the macroscopic material. The impact of the specific morphology of the blends, known as “raspberry morphology”, on the final material will be explained using thermomechanical analysis and revealing relevant deformation mechanisms. The correlations between domain size, toughness of the blends and the corresponding toughening mechanisms are explained. After compatibilization, the fracture toughness is increased due to better bonding and stress transfer between the phases and smaller domain sizes with strong interface impose shear yielding of the matrix. Very small inter-domain distances hinder matrix deformations, which forces debonding as a “weaker” main deformation mechanism. It is found that a PPE/SAN ratio of 60/40 (w/w) has the optimum viscosity during processing to control the morphology. At this blend ratio the dispersed PPE domains have a low packing density, allowing shear deformations of the matrix.

Polymer blends have the potential to be homogenously foamed, since the interface area between their phases can be used as bubble nucleating agents during the foaming process. Immiscible polymer blends of poly(2,6-dimethyl-1,4-phenylene ether) PPE and poly(styrene-co-acrylonitrile) SAN with a weight ratio of 60/40 are compatibilized by different amounts (1–10 wt%) of Janus nanoparticles (JPs). Here, we report on the nucleation effect of JPs and the dispersed PPE phase on the foaming behavior of PPE/SAN blends. The plasticization of CO2 and its solubility and diffusion behavior in the PPE/SAN blend are analyzed and correlated to blend morphologies. It is shown that partial coverage of the raspberry structure results in stress concentration at the blend interface during the saturation step. This formation of new surfaces by cleavage (and maybe microcrazes) results in a higher sorption of the blowing agent, which affects the foaming behavior. Through temperature-induced batch foaming with CO2, the blends are foamed to find the optimum foaming conditions and relationships between the morphology of the compact and foamed blends (cellular structure) and the density are established. Finally, it was concluded that by using Janus particles, homogenous foams with small cell sizes, and relatively high densities are produced.

Eine neue, Templat-gestutzte Synthese monodisperser Nanopartikel stellt keine Anforderungen an die Selbstorganisation und ist hoch reproduzierbar. Hierzu werden masgeschneiderte Polymerkafige fur die Synthese von Nanopartikeln verwendet, die aus vernetzten Makromolekulen mit Thiolendgruppen bestehen. Goldnanopartikel (AuNPs) wurden in verschiedenen Verhaltnissen von Polymerkafig zu Gold in situ in den Polymerkafigen synthetisiert. Die Polymerkafige zeichneten sich dabei durch eine definierte Beladungskapazitat aus, mit exzellenter Kontrolle uber Form und Grose. Dagegen zeigten Kontrollversuche mit linearen Diblockcopolymeren einen linearen Anstieg der Partikelgrosen mit steigendem Goldanteil. Das unterschiedliche Wachstumsverhalten der AuNPs wird durch die Vernetzungsgrad-abhangige Flexibilitat der Polymerketten erklart. Des Weiteren wird die Polymerkafig-gesteuerte In-situ-Synthese auf Silber- (AgNPs), Palladium- (PdNPs) und Platinnanopartikel (PtNPs) ubertragen.

A series of strong polycations is synthesized through the anionic polymerization of 2-vinylpyridine, followed by subsequent quaternization of the resulting polymer. Polycations based on quaternized 2-vinylpyridine (PVPQs) with degrees of polymerization (DP) from 20 to 440 are adsorbed on the surface of small anionic liposomes. Liposome/PVPQ complexes are characterized by using a number of physicochemical methods. All PVPQs are totally adsorbed onto the liposome surface up to a certain concentration at which saturation is reached (which is specific for each PVPQ). The integrity of the adsorbed liposomes remains intact. Short PVPQs interact with anionic lipids localized on the outer membrane leaflet, whereas long PVPQs extract anionic lipids from the inner to outer leaflet. Complexes tend to aggregate, and the largest aggregates are formed when the initial charge of the liposomes is fully neutralized by the charge of the PVPQ. PVPQs with intermediate DPs demonstrate behavioral features of both short and long PVPQs. These results are important for the interpretation of the biological effects of cationic polymers and the selection of cationic polymers for biomedical applications.

The self-assembly of block copolymers in the bulk phase enables the formation of complex nanostructures with sub 100 nm periodicities and long-range order, both relevant for nanotechnology applications. Here, we map the bulk phase behavior of polystyrene-block-polybutadiene-block-poly(tert-butyl methacrylate) (SBT) triblock terpolymers on a series of narrowly distributed polymers with widely different block volume fractions, ϕS, ϕB and ϕT. In dependence of ϕ, we find the lamella–lamella, core-shell cylinder, cylinder-in-lamella and core-shell gyroid morphology, but also a rarely observed cylinder-in-lamella phase. The bulk morphologies are thoroughly characterized by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) and display unusually broad stability regions, i.e. morphologies are observed over a broad range of compositions. We attribute this phase behavior to the asymmetric distribution of block–block incompatibilities, along the SBT block sequence, which are relatively large for S/B and S/T interfaces, but small for B/T. The higher enthalpic penalties at the S/B and S/T interface cause B to preferentially spread on the T microdomain thereby adopting its geometry. The morphological behavior of SBT is thus dominated by the volume ratio of the end blocks, ϕS and ϕT, which reduces the number of potential morphologies to only a few, mostly the core-shell analogue of diblock copolymer morphologies. In general, a simplified terpolymer bulk behavior with large stability regions for morphologies offers straightforward synthetic targeting of specific morphologies that usually only appear in a small parameter space as demonstrated here on the core-shell gyroid.