Hierarchical self‐assembly of transient composite hydrogels is demonstrated through a two‐step, orthogonal strategy using nanoparticle tectons interconnected through metal–ligand coordination complexes. The resulting materials are highly tunable with moduli and viscosities spanning many orders of magnitude, and show promising self‐healing properties, while maintaining complete optical transparency.
By anchoring alkynylplatinum(II) terpyridine molecular tweezer/pyrene recognition motif on the chain‐ends of telechelic polycaprolactone, high‐molecular‐weight supramolecular polymers have been successfully constructed via noncovalent chain extension, which demonstrate fascinating rheological and thermal properties. Moreover, the resulting assemblies exhibit interesting temperature‐ and solvent‐responsive behaviors, which are promising for the development of adaptive functional materials.
Stratified polymer brushes are fabricated using microcontact printing (μCP) of initiator integrated polydopamine (PDOPBr) on polymer brush surfaces and the following surface initiated atom transfer radical polymerization (SI‐ATRP). It is found that the surface energy, chemically active groups, and the antifouling ability of the polymer brushes affect transfer efficiency and adhesive stability of the polydopamine film. The stickiness of the PDOPBr pattern on polymer brush surfaces is stable enough to perform continuous μCP and SI‐ATRP to prepare stratified polymer brushes with a 3D topography, which have broad applications in cell and protein patterning, biosensors, and hybrid surfaces.
Here, a novel multi‐stimuli‐responsive fluorescence probe is developed by incorporating spiropyran group into the coumarin‐substituted polydiacetylene (PDA) vesicles. The fluorescence of PDA can be turned on upon heating, and can be quenched upon exposure to UV light irradiation or pH stimuli owing to the fluorescene resonance energy transfer (FRET) between the red‐phase PDA and the open merocyanine (MC) form of spiropyran. Moreover, we have designed and experimentally realized a set of logic gate operations for the first time based on the fluorescence modulation of the designed system upon thermal, photo, and pH stimuli. This novel type of resettable logic gates augur well for practical applications in information storage, optical recording, and sensing in complicated microenvironments.
A novel route for the synthesis of poly(ethylene glycol)‐b‐polystyrene copolymer, starting from commercially available poly(ethylene glycol) methyl ether and azido terminated polystyrene prepared by atom transfer radical polymerization and subsequent nucleophilic substitution, is applied with simplicity and high efficiency. The combination of photoinduced copper (I)‐catalyzed alkyne‐azide cycloaddition (CuAAC) and ketene chemistry reactions proceeds either simultaneously or sequentially in a one‐pot procedure under near‐visible light irradiation. In both cases, excellent block copolymer formations are achieved, with an average molecular weight of around 7000 g mo1−1 and a polydispersity index of 1.20.
For most stimuli‐responsive polymer materials (SRPMs), such as polymer gels, micelles, and brushes, the responsive mechanism is based on the solubility or compatibility with liquid media. That basis always results in distorting or collapsing the material's appearance and relies on external liquids. Here, a novel kind of SRPMs is proposed. Unlike most SRPMs, liquid is stored within special domains rather than expelled, so it is deforming‐free and relying on no external liquid, which is referred to as self‐storage SRPMs (SS‐SRPMs). The facile and universal route to fabricate SS‐SRPMs allows for another novel family of SRPMs. Furthermore, it is validated that SS‐SRPMs can drastically respond to outside temperature like switchers, especially for optical and electrochemical responses. Those features hold prospects for applications in functional devices, such as smart optical lenses or anti‐self‐discharge electrolytes for energy devices.
Three different series of brush polymers bearing glucosyl, maltosyl, or maltotriosyl moiety at the bristle end are successfully prepared by using cationic ring‐opening polymerization and two sequential postmodification reactions. All brush polymers, except for the polymer containing 100 mol% maltotriosyl moiety, demonstrate the formation of multibilayer structure in films, always providing saccharide‐enriched surface. These self‐assembling features are remarkable, regarding the bulkiness of saccharide moieties and the kink in the bristle due to the triazole linker. The saccharide‐enriched film surfaces reveal exceptionally high specific binding affinity to concanavalin A but suppress nonspecific binding of plasma proteins severely. Overall, the brush polymers bearing saccharide moieties of various kinds in this study are highly suitable materials for biomedical applications including biosensors.
A range of amphiphilic polymers with diverse macromolecular architectures has been developed and incorporated into films and coatings with potential for marine antibiofouling applications, without resorting to addition of currently used biocidal, toxic agents. Novel “green” chemical technologies employ different building blocks to endow the polymer film with surface activity, functionality, structure, and reconstruction according to the outer environment as a result of a tailored amphiphilic character of the polymer platform. We emphasise how these features can interplay and add synergistically to affect antifouling and fouling‐release against common, widespread marine micro‐ and macro‐fouling organisms.
A straightforward synthetic procedure for the double modification and polymer–polymer conjugation of telechelic polymers is performed through amine‐thiol‐ene conjugation. Thiolactone end‐functionalized polymers are prepared via two different methods, through controlled radical polymerization of a thiolactone‐containing initiator, or by modification of available end‐functionalized polymers. Next, these different linear polymers are treated with a variety of amine/acrylate‐combinations in a one‐pot procedure, creating a library of tailored end‐functionalized polymers. End group conversions are monitored via SEC, NMR, and MALDI‐TOF analysis, confirming the quantitative modification after each step. Finally, this strategy is applied for the synthesis of block copolymers via polymer–polymer conjugation and the successful outcome is analyzed via LCxSEC measurements.
Inspired by the molecular mechanics of mussel adhesive formation, a novel water‐soluble fluorescent macromolecule (polydopamine–polyethyleneimine (PDA–PEI)) is prepared by one‐pot copolymerization of dopamine (DA) and PEI. In this method, DA is polymerized to form PDA, which is then coupled with PEI mainly through Michael addition. The fluorescence property of PDA–PEI is mainly attributed to the Michael addition of PEI on the 5,6‐dihydroxyindole (DHI) units of PDA, where PEI can form hydrogen bonds with oxidative products such as DHI and force the DHI units to twist out of plane, resulting in a decrease in the intra‐ and intermolecular coupling of PDA. In addition, the influence of various metal cations on the fluorescence of the PDA–PEI copolymer is investigated. This work may facilitate the development of new strategies for controlling the emission characteristics of PDA.
Multivalent binding is a key for many critical biological processes and unique recognition and specificity in binding enables many of different glycans and proteins to work in a great harmony within the human body. In this study, the binding kinetics of synthetic glycopolypeptides to the dendritic cell lectin DC‐SIGN and their inhibition potential for DC‐SIGN interactions with the gp120 envelope glycoprotein of HIV‐1 (gp120) are investigated.
This study proposes a method to coat thin films of non‐volatile solvents on substrates. A small amount of crystalline polymer dissolved in solvents forms a network of crystalline fibrils during the coating process. The network suppresses dewetting of the solvent liquid and helps the liquid film sustaining on the substrate. This strategy can be used in soft lithography to generate micropatterns of diverse materials without having a residual layer. This process does not request etching for achieving residual layer‐free micropatterns, which has been a long challenge in soft lithography. As examples, we demonstrate micropatterns of polymer hydrogels and metal oxides (ZnO, In2O3
Bilayer photomechanical films are fabricated by depositing one layer of molecular azobenzene chromophores onto flexible low‐density polyethylene substrates. The photoinduced bending and unbending behavior of five azobenzene derivatives including azobenzene, 4‐hydroxy‐azobenzene, 4‐((4‐hydroxyphenyl)diazenyl)bezoitrile, 4‐((4‐methoxyph‐enyl)diazenyl)phenol, and 4‐(phenyldiazenyl)phenol is systematically studied by considering the incident light intensity and the thickness of the coated chromophore layers. Precise control of photoinduced curling of the bilayer film is successfully achieved upon irradiation with two beams of UV light, and the curled films can be recovered by thermal relaxation in the dark. The easily fabricated bilayer films show fast photomechanical response, strong photoinduced stress, and stability similar to crosslinked polymeric films.
A thermo‐controlled pesticide release system composed of poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA) thin film grafted polydopamine (PDA) (PDMAEMA‐g‐PDA) microcapsules is reported. SiO2 microparticles are used as a template to prepare PDA‐coated SiO2 microparticles. The thermally‐responsive PDMAEMA thin films are grafted on PDA surfaces using a metal‐free surface‐initiated photopolymerization approach without adding any photoinitiator or photosensitizer under UV light irradiation. The subsequent acid etching yields PDMAEMA‐g‐PDA hollow microcapsules. PDMAEMA‐g‐PDA microcapsules exhibit well‐controlled release of avermectin (Av). The results show that the loading ability of PDMAEMA‐g‐PDA microcapsules of Av is up to 52.7% (w/w). The release kinetics of Av demonstrate that Av@PDMAEMA‐g‐PDA microcapsules exhibit temperature‐controlled release performance. This work is significant for controlled release systems. This simple design is expected to be used in various applications, such as in controlled drug release and agriculture‐related fields.
In this paper, an oxygen‐insensitive degradable resist for UV‐nanoimprint is designed, comprising a polycyclic degradable acrylate monomer, 2,10‐diacryloyloxymethyl‐1,4,9,12‐tetraoxaspiro [4.2.4.2] tetradecane (DAMTT), and a multifunctional thiol monomer pentaerythritol tetra(3‐mercaptopropionate) (PETMP). The resist can be quickly UV‐cured in the air atmosphere and achieve a high monomer conversion of over 98%, which greatly reduce the adhesion force between the resist and the soft mold. High conversion, in company with an adequate Young's modulus (about 1 GPa) and an extremely low shrinkage (1.34%), promises high nanoimprint resolution of sub‐50 nm. The cross‐linked resist is able to break into linear molecules in a hot acid solvent. As a result, metallic patterns are fabricated on highly curved surfaces via the lift off process without the assistance of a thermoplastic polymer layer.
Poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA)‐based brush poly(phosphoamidate)s are successfully synthesized by a combination of ring‐opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP) following either a commutative two‐step procedure or a straightforward one‐pot process using Grubbs ruthenium‐based catalysts for tandem catalysis. Compared with the traditional polymerization method, combining ROMP and ATRP in a one‐pot process allows the preparation of brush copolymers characterized by a relatively moderate molecular weight distribution and quantitative conversion of monomer. Moreover, the surface morphologies and aggregation behaviors of these polymers are studied by AFM and TEM measurements.
Diarylbutadiyne derivatives are ideal monomers for providing the π‐electron‐conjugated system of polydiacetylenes (PDAs). The geometrical parameters for diacetylene topochemical polymerization are known. However, control of the molecules under these parameters is yet to be addressed. This work shows that by simply tailoring diarylbutadiyne with amide side‐chain substituents, the arrangement of the substituents and the resulting hydrogen bond framework allows formation of π‐electron‐conjugated PDA.
Molecular bottle‐brush functionalized single‐walled carbon nanotubes (SWCNTs) with superior dispersibility in water are prepared by a one‐pot synthetic methodology. Elongating the main‐chain and side‐chain length of molecular bottle‐brushes can further increase SWCNT dispersibility. They show significant enhancement of SWCNT dispersibility up to four times higher than those of linear molecular functionalized SWCNTs.
Thin, phenylboronic acid‐containing polymer coatings are potentially attractive sensory layers for a range of glucose monitoring systems. This contribution presents the synthesis and properties of glucose‐sensitive polymer brushes obtained via surface RAFT polymerization of 3‐methacrylamido phenylboronic acid (MAPBA). This synthetic strategy is attractive since it allows the controlled growth of PMAPBA brushes with film thicknesses of up to 20 nm via direct polymerization of MAPBA without the need for additional post‐polymerization modification or deprotection steps. QCM‐D sensor chips modified with a PMAPBA layer respond with a linear change in the shift of the fundamental resonance frequency over a range of physiologically relevant glucose concentrations and are insensitive toward the presence of fructose, thus validating the potential of these polymer brush films as glucose sensory thin coatings.
1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (TBD)‐catalyzed polycondensation reactions of fatty acid derived dimethyl dicarbamates and diols are introduced as a versatile, non‐isocyanate route to renewable polyurethanes. The key step for the synthesis of dimethyl carbamate monomers from plant‐oil‐derived dicarboxylic acids is based on a sustainable base‐catalyzed Lossen rearrangement. The formed polyurethanes with molecular weights up to 25 kDa are characterized by SEC, DSC, and NMR analysis.
