A facile cellulose finishing strategy through in-situ growth of sliver-doped manganese dioxide assisted by amine-quinone for improving indoor living quality

Nowadays, various harmful indoor pollutants especially including bacteria and residual formaldehyde (HCHO) seriously threaten human health and reduce the quality of public life. Herein, a universal substrate-independence finishing approach for efficiently solving these hybrid indoor threats is demonstrated, in which amine-quinone network (AQN) was employed as reduction agent to guide in-situ growth of Ag@MnO2 particles, and also acted as an adhesion interlayer to firmly anchor nanoparticles onto diverse textiles, especially for cotton fabrics. In contrast with traditional hydrothermal or calcine methods, the highly reactive AQN ensures the efficient generation of functional nanoparticles under mild conditions without any additional catalysts. During the AQN-guided reduction, the doping of Ag atoms onto cellulose fiber surface optimized the crystallinity and oxygen vacancy of MnO2, providing cotton efficient antibacterial efficiency over 90 % after 30 min of contact, companying with encouraging UV-shielding and indoor HCHO purification properties. Besides, even after 30 cycles of standard washing, the Ag@MnO2-decorated textiles can effectively degrade HCHO while well-maintaining their inherent properties. In summary, the presented AQN-mediated strategy of efficiently guiding the deposition of functional particles on fibers has broad application prospects in the green and sustainable functionalization of textiles.

Functional Nanoporous Materials From Boronate-Containing Stimuli-Responsive Diblock Copolymers

Functional nanoporous polymeric materials have been prepared from novel polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer precursors containing a reversible boronate ester junction between both blocks. To this purpose, homopolymers presenting either...

Boronic Acid-Mediated Activity Control of Split 10-23 DNAzymes

The 10-23 DNAzyme is an artificially developed Mg2+ -dependent catalytic oligonucleotide that can cleave an RNA substrate in a sequence-specific fashion. In this study, new split 10-23 DNAzymes made of two nonfunctional fragments, one of which carries a boronic acid group at its 5' end, while the other has a ribonucleotide at its 3' end, were designed. Herein it is demonstrated that the addition of Mg2+ ions leads to assembly of the fragments, which in turn induces the formation of a new boronate internucleoside linkage that restores the DNAzyme activity. A systematic evaluation identified the best-performing system. The results highlight key features for efficient control of DNAzyme activity through the formation of boronate linkages.

Linear Coordination Polymer Synthesis from Bis-Catechol Functionalized RAFT Polymers

Catechol-Fe(III) complexes contain some of the strongest known metal-chelate coordination bonds. Despite this, they have until now not been utilized in (polymeric linker) linear coordination polymer (LCP) synthesis. With the view of generating catechol end-functional polymers, a new, symmetrical bis-catechol functionalized trithiocarbonate reversible addition fragmentation chain transfer (RAFT) agent is synthesized (CatDMAT). Acrylamide (AM) and dimethylacrylamide (DMA) polymerizations are conducted with CatDMAT using direct photoactivation RAFT polymerization to yield bis-catechol end-functionalized homo- and block-copolymers of molecular weight 10-15 kDa. Catechol-Fe(III) LCPs are successfully formed from the telechelic catechol polymers by bis-complexation to Fe(III). The tetrahedral bis-complex is detected by UV-vis spectroscopy (λ_max  = 570 nm), while increases in relative viscosity and M_n,GPC over their respective uncomplexed polymers confirm the occurrence of supramolecular polymerization. The catechol-LCPs are shown to undergo oxidation and crosslinking in aqueous solution after 24 h.

Discrete boronate ester ladders from the dynamic covalent self-assembly of oligo(phenylene ethynylene) derivatives and phenylenebis(boronic acid)

Reversible boronate ester chemistry enables the controlled, dynamic self-assembly of olig(phenylene ethynylene)s into highly conjugated ladder frameworks.

Bioinspired Metal⁻Polyphenol Materials: Self-Healing and Beyond

The blue mussel incorporates the polyphenolic amino acid l-3,4-dihydroxyphenylalanine (DOPA) to achieve self-healing, pH-responsiveness, and impressive underwater adhesion in the byssus threads that ensure the survival of the animal. This is achieved by a pH-dependent and versatile reaction chemistry of polyphenols, including both physical interactions as well as reversible and irreversible chemical bonding. With a short introduction to the biological background, we here review the latest advances in the development of smart materials based on the metal-chelating capabilities of polyphenols. We focus on new ways of utilizing the polyphenolic properties, including studies on the modifications of the nearby chemical environment (on and near the polyphenolic moiety) and on the incorporation of polyphenols into untraditional materials.

Preparation of lactic acid- and glucose-responsive poly(ε-caprolactone)-b-poly(ethylene oxide) block copolymer micelles using phenylboronic ester as a sensitive block linkage

The present study describes the synthesis, self-assembly and responsiveness to glucose and lactic acid of biocompatible and biodegradable block copolymer micelles using phenylboronic ester as the linkage between hydrophobic poly(ε-caprolactone) (PCL) and hydrophilic poly(ethylene oxide) (PEO). The PCL block with pendant phenylboronic acid (PCLBA) was synthesized by combining ε-caprolactone (ε-CL) ring-opening polymerisation (ROP), using 4-hydroxymethyl(phenylboronic) acid pinacolate as the initiator, and pinacol deprotection. The glucose-terminated PEO (PEOGlc) was prepared by 1,3-dipolar, Cu(i)-catalysed, alkyne-azide cycloaddition of α-methoxy-ω-propargyl poly(ethylene oxide) and 1-azido-1-deoxy-d-glucopyranose. All new compounds were evaluated by 1H NMR spectroscopy and by SEC analysis. PCLBA and PEOGlc blocks were linked in NaOH acetone solution, which was indirectly confirmed by Alizarin Red S fluorescence and directly by 1H NMR spectroscopy. Dialysis against Milli-Q water induced the self-assembly of PCLBA-b-PEOGlc nanoparticles, which were characterised by static (SLS) and dynamic (DLS) light scattering and by cryogenic transmission electron microscopy (cryo-TEM). Furthermore, the microscopic properties of the charged interface between the hydrophobic PCLBA core and the hydrophilic PEOGlc shell were examined by electrophoretic light scattering (zeta potential) and by fluorescence spectroscopy using the fluorescent probe 5-(N-dodecanoyl)aminofluorescein (DAF) as a pH indicator. Subsequently, the nanoparticles were transferred to a phosphate buffer saline (PBS) solution supplemented with different concentrations of glucose to simulate the physiological conditions in blood or lactic acid to simulate acidic cytosolic or endosomal conditions in tumour cells. Adding a surplus of glucose or lactic acid, which competitively binds to PBA, removes the stabilising hydrophilic PEOGlc blocks, thereby triggering marked nanoparticle aggregation. However, the rate of aggregation induced by lactic acid is considerably faster than that induced by glucose, as confirmed by light scattering. Thus, this novel block copolymer may contribute to the field of selective, lactic acid- and/or glucose-responsive drug delivery vehicle design under both pathological and physiological conditions.

Micellization of Photo-Responsive Block Copolymers

This review focuses on block copolymers featuring different photo-responsive building blocks and self-assembly of such materials in different selective solvents. We have subdivided the specific examples we selected: (1) according to the wavelength at which the irradiation has to be carried out to achieve photo-response; and (2) according to whether irradiation with light of a suitable wavelength leads to reversible or irreversible changes in material properties (e.g., solubility, charge, or polarity). Exemplarily, an irreversible change could be the photo-cleavage of a nitrobenzyl, pyrenyl or coumarinyl ester, whereas the photo-mediated transition between spiropyran and merocyanin form as well as the isomerization of azobenzenes would represent reversible response to light. The examples presented cover applications including drug delivery (controllable release rates), controlled aggregation/disaggregation, sensing, and the preparation of photochromic hybrid materials.

Thermoresponsive Pyrrolidone Block Copolymer Organogels from 3D Micellar Networks

A new series of amphiphilic pyrrolidone diblock copolymers poly[N-(2-methacrylaoyxyethyl)pyrrolidone]-block-poly(methyl methacrylate) (PNMP m -b-PMMA n ; where m is fixed at 37 and n is varied from 45 to 378) is developed. Spontaneously situ-gelling behaviors are observed in isopropanol when n varies from 117 to 230, whereas only dissolution or precipitation appears when n is beyond this region. Further analysis reveals that uniform thermoinduced reversible gel-sol transitions are observed in those organogels, which is attributed to the disassembly from micellar networks to micelles as confirmed by electron microscopy and other techniques. The gel-sol transition temperature is highly dependent on n and increases as n increases. Conformational interactions analyzed using 1H NMR and 2D Noesy NMR suggest that the thermoinduced stretch of solvophilic PNMP segments within micelles and the sequencing variation in the isopropanol molecules are the major cause of the gel-sol transitions.

Temperature, ultrasound and redox triple-responsive poly(N-isopropylacrylamide) block copolymer: synthesis, characterization and controlled release

Triple stimuli-responsive polymers PNiPAAm-S-S-PXCL containing a disulfide (–S–S–) bond as a junction point between hydrophilic and hydrophobic chains were synthesized and characterized.