We report the functionalization of polypyrrole (PPy) with a “sticky” biomolecule dopamine (DA), which mimics the essential component of mussel adhesive protein. PPy is one of the most promising electrically conductive polymers with good biocompatibility. The research findings reveal that the DA functionalization enhances the dispersibility and stability of PPy in water and its film adhesion to substrate surface significantly. The electrical conductivity of PPy increases to a maximum value and then decreases with the increasing DA concentration. An optimal DA to pyrrole (Py) mole ratio is found to be between 0.1 and 0.2, at which both conductivity and adhesion of DA‐functionalized PPy has been improved.
Artificial special wetting surfaces have drawn much interest due to their important applications in many fields. Nevertheless, tremendous challenges still remain for the fabrication of wetting surfaces with durable and self‐healing properties. Here, recent progress of durable, self‐healing wetting surfaces is highlighted by discussing the fabrications of several typical wetting surfaces including superhydrophobic surfaces, superamphiphobic surfaces, underwater superoleophobic surfaces, and high hydrophilic antifouling surfaces based on expertise and related research experience. To conclude, some perspectives on the future research and development of these special wetting surfaces are presented.
The unique mechanical performance of nacre, the pearly internal layer of shells, is highly dependent on its complex morphology. Inspired by the structure of nacre, the fabrication of well‐ordered layered inorganic–organic nanohybrids is presented herein. This biomimetic approach includes the use of a block copolymer template, consisting of hydrophobic poly(vinylidene fluoride) (PVDF) lamellae covered with hydrophilic poly(methacrylic acid) (PMAA), to direct silica (SiO2) mineralization. The resulting PVDF/PMAA/SiO2 nanohybrid material resembles biogenic nacre with respect to its well‐ordered and layered nanostructure, alternating organic–inorganic phases, macromolecular template, and mild processing conditions.
A new approach to stabilize carbon nanotubes (CNTs) in aqueous solution with a reduction‐responsive water‐soluble polymer is reported. The novel polymer synthesized by a controlled radical polymerization is functionalized with pendant pyrene groups capable of adhering to the surface of CNTs through π–π noncovalent interactions, and labeled with disulfide linkages to exhibit reduction‐responsive cleavage. Upon the cleavage of junction disulfide linkages in a reducing environment, water‐soluble polymers are shed, retaining clean CNT surfaces for electrochemical catalytic reactions.
Hierarchical semicrystalline block copolymer nanoparticles are produced in a segmented gas‐liquid microfluidic reactor with top‐down control of multiscale structural features, including nanoparticle morphologies, sizes, and internal crystallinities. Control of multiscale structure on disparate length scales by a single control variable (flow rate) enables tailoring of drug delivery nanoparticle function including release rates.
A simple and effective airflow method to prepare sandwich‐type block copolymer films is reported. The films are composed of three layers: vertically oriented nanocylinders align in both upper and bottom layers and irregular nanocylinders exist in the bulk of the film. The vertically oriented nanocylinders in both sides can provide high accessibility to ions and ensures the exchange of chemical species between the membrane and external environment, while the irregularly oriented nanocylinders in the middle part of the film can prolong the pathway of ions transportation and enhance ions selectivity.
A recent response on a publication from our team investigating solvent effects on propagation rate coefficients is commented. Among other issues, we point to the fact that the response interprets only a subset of the data provided in our original contribution.
Since the development of supramolecular chemical biology, self‐organised nano‐architectures have been widely explored in a variety of biomedical applications. Functionalized synthetic molecules with the ability of non‐covalent assembly in an aqueous environment are typically able to interact with biological systems and are therefore especially interesting for their use in theranostics. Nanostructures based on π‐conjugated oligomers are particularly promising as theranostic platforms as they bear outstanding photophysical properties as well as drug loading capabilities. This Feature Article provides an overview on the recent advances in the self‐assembly of intrinsically fluorescent nanoparticles from π‐conjugated small molecules such as fluorene or perylene based chromophores for biomedical applications.
Polymers with pendant phenoxyl radicals are synthesized and the electrochemical properties are investigated in detail. The monomers are polymerized using ring‐opening metathesis polymerization (ROMP) or free‐radical polymerization methods. The monomers and polymers, respectively, are oxidized to the radical either before or after the polymerization. These phenoxyl radicals containing polymers reveal a reversible redox behavior at a potential of −0.6 V (vs Ag/AgCl). Such materials can be used as anode‐active material in organic radical batteries (ORBs).
In this study, a new type of functional, self‐assembled nanostructure formed from porphyrins and polyamidoamine dendrimers based on hydrogen bonding in an aqueous solution is presented. As the aggregates formed are promising candidates for solar‐energy conversion, their photocatalytic activity is tested using the model reaction of methyl viologen reduction. The self‐assembled structures show significantly increased activity as compared to unassociated porphyrins. Details of interaction forces driving the supramolecular structure formation and regulating catalytic efficiency are fundamentally discussed.
Reversible addition‐fragmentation chain transfer polymerization yields reactive block copolymers bearing the pentafluorophenyl ester (PFPA) group, and subsequent Click amidation using 2,2,6,6‐tetramethylpiperidine‐N‐oxyl‐ and imidazolium‐functionalized primary amines produces the corresponding functional block copolymers, leading to installation of statistical radical‐ and ionic sites into the PFPA segment. The monolayered thin film devices fabricated using the obtained block copolymers exhibit repeatable switching of electric conductivity (on/off ratio > 103) under a bias voltage, which reveals that the coexistence of radicals and ions in the same spherical domain of the copolymer layer is a prerequisite for repeatable switching memory.
A linear supramolecular polymer based on the self‐assembly of an easily available copillar[5]arene monomer is efficiently prepared, which is evidenced by the NMR spectroscopy, viscosity measurement, and DOSY experiment. The single‐crystal X‐ray analysis reveals that the polymerization of the AB‐type monomer is driven by the quadruple CH•••π interactions and one CH•••O interaction.
In situ Pd‐catalyzed cyclopentene polymerization in the presence of multi‐walled carbon nanotubes (MWCNTs) is demonstrated to effectively render, on a large scale, polycyclopentene‐crystal‐decorated MWCNTs. Controlling the catalyst loading and/or time in the polymerization offers a convenient tuning of the polymer content and the morphology of the decorated MWCNTs. Appealingly, films made of the decorated carbon nanotubes through simple vacuum filtration show the characteristic lotus‐leaf‐like superhydrophobicity with high water contact angle (>150°), low contact angle hysteresis (<10°), and low water adhesion, while being electrically conductive. This is the first demonstration of the direct fabrication of lotus‐leaf‐like superhydrophobic films with solution‐grown polymer‐crystal‐decorated carbon nanotubes.
A double‐layer hollow fiber is fabricated where an isoporous surface of polystyrene‐block‐poly(4‐vinylpyridine) is fixed on a support layer by co‐extrusion. Due to the sulfonation of the support layer material, delamination of the two layers is suppressed without increasing the number of subsequent processing steps for isoporous composite membrane formation. Electron microscope‐energy‐dispersive X‐ray spectroscopy images unveil the existence of a high sulfur concentration in the interfacial region by which in‐process H‐bond formation between the layers is evidenced. For the very first time, our study reports a facile method to fabricate a sturdy isoporous double‐layer hollow fiber.
In a recent publication, Nakamura and co‐workers studied the termination mechanism in the radical polymerization of acrylates. Contrary to conventional thinking, their conclusion is that termination is overwhelmingly by disproportionation. This finding impacts on a large body of the previous work in the polymerization of acrylic monomers which this work seeks to address. Analysis of the molecular weight distribution of acrylic polymers obtained under different polymerization conditions shows that termination by combination is the more probable mechanism for mutual termination of secondary radicals. It is proposed that in the experiments conducted by Nakamura and co‐workers, backbiting plays a key role and their experimental data are reinterpreted, showing that they are more revealing with respect to the mode of termination of the midchain radical produced by backbiting, than to bimolecular termination of secondary radicals.
A new method for fabricating hydrogels with intricate control over hierarchical 3D porosity using microfiber porogens is presented. Melt electrospinning writing of poly(ε‐caprolactone) is used to create the sacrificial template leading to hierarchical structuring consisting of pores inside the denser poly(2‐oxazoline) hydrogel mesh. This versatile approach provides new opportunities to create well‐defined multilevel control over interconnected pores with diameters in the lower micrometer range inside hydrogels with potential applications as cell scaffolds with tunable diffusion and transport of, e.g., nutrients, growth factors or therapeutics.
Photoresponsive azobenzene‐containing systems ranging from molecular to macroscopic material levels have greatly been increasing their significance in materials chemistry. This review focuses on the studies on light induced or triggered motions in azobenzene liquid crystalline (LC) polymer films at mesoscopic and microscopic levels. Due to the cooperative nature of liquid crystalline materials, highly efficient photoalignment and photo‐triggered migrating motions are realized in mostly repeated manners. Here, recent advances in surface‐grafted LC polymer brushes, LC block copolymer films, and LC polymer films that exhibit mass migrations are overviewed. Such newly emerged photoresponsive systems are expected to provide new possibilities and applications in polymer thin film technologies.
A free‐standing polymer brush film with tailored thicknesses based on a colorless polydopamine (PDA) thin layer is prepared and characterized. The surface‐initiated atom transfer radical polymerization (ATRP) of 2‐hydroxyethyl methacrylate (HEMA) is performed on a PDA layer with thickness of ca. 6 nm, which generated an optically transparent and colorless free‐standing PHEMA brush film (1.5 cm × 1.5 cm). Because the cross‐linked PDA layer is used as the base for the polymer brushes, the reported method does not require cross‐linking the polymer brushes. The free‐standing film thicknesses of ≈16–75 nm are controlled by simply changing the ATRP reaction time. The results show that the free‐standing PHEMA brush film transferred onto a plate exhibits a relatively smooth surface and is stable in any solvent.
The chemical control of cell division has attracted much attention in the areas of single cell‐based biology and high‐throughput screening platforms. A mussel‐inspired cytocompatible encapsulation method for achieving a “cell‐division control” with cross‐linked layer‐by‐layer (LbL) shells is developed. Catechol‐grafted polyethyleneimine and hyaluronic acid are chosen as polyelectrolytes for the LbL process, and the cross‐linking of polyelectrolytes is performed at pH 8.5. Cell division is controlled by the number of the LbL nanolayers and cross‐linking reaction. We also suggest a new measuring unit, , for quantifying “cell‐division timing” based on microbial growth kinetics.
In this work, syndiotactic polypropylene (sPP) as well as isotactic polypropylene (iPP) are cross‐linked to gain a shape memory effect. Both prepared PP networks exhibit maximum strains of 700%, stored strains of up to 680%, and recoveries of nearly 100%. While x‐iPP is stable for many cycles, x‐sPP ruptures after the first shape‐memory cycle. It is shown by wide‐angle X‐ray scattering (WAXS) experiments that cross‐linked iPP exhibits homoepitaxy in the temporary, stretched shape but in contrast to previous reports it contains a higher amount of daughter than mother crystals.
