Ionogels: recent advances in design, material properties and emerging biomedical applications.

Ionic liquid (IL)-based gels (ionogels) have received considerable attention due to their unique advantages in ionic conductivity and their biphasic liquid-solid phase property. In ionogels, the negligibly volatile ionic liquid is retained in the interconnected 3D pore structure. On the basis of these physical features as well as the chemical properties of well-chosen ILs, there is emerging interest in the anti-bacterial and biocompatibility aspects.

2D conjugated microporous polyacetylenes synthesized via halogen-bond-assisted radical solid-phase polymerization for high-performance metal-ion absorbents.

The paper reports the first free-radical solid-phase polymerization (SPP) of acetylenes. Acetylene monomers were co-crystalized using halogen bonding, and the obtained cocrystals were polymerized. Notably, because of the alignment of acetylene monomers in the cocrystals, the adjacent C≡C groups were close enough to undergo radical polymerization effectively, enabling the radically low-reactive acetylene monomers to generate high-molecular-weight polyacetylenes that are unattainable in solution-phase radical polymerizations.

Surface antimicrobial functionalization with polymers: fabrication, mechanisms and applications.

Undesirable adhesion of microbes such as bacteria, fungi and viruses onto surfaces affects many industries such as marine, food, textile, and healthcare. In particular in healthcare and food packaging, the effects of unwanted microbial contamination can be life-threatening. With the current global COVID-19 pandemic, interest in the development of surfaces with superior anti-viral and anti-bacterial activities has multiplied.

Microscopically tuning the graphene oxide framework for membrane separations: a review.

Membrane-based separations have been widely applied in gas, water and organic solvent purifications to reduce energy consumption and minimize environmental pollution. In recent years, graphene oxide (GO) membranes have attracted increasing attention due to their self-assembly ability and excellent stability. In this review, publications within the last 3 years on microscopically tuning the GO framework are summarized and reviewed.

Polyelectrolyte Hydrogels for Tissue Engineering and Regenerative Medicine.

Polyelectrolyte hydrogels are emerging materials for tissue engineering and regenerative medicine applications due to their tunable biochemical properties, electrical conductivity, biocompatibility and similar network structure to the extracellular matrix in mammalian bodies. In this review, representative polyelectrolyte hydrogels carrying anionic, cationic, ampholytic, zwitterionic and ionic liquid moieties are systemically cataloged to express their chemical structures and preparation strategies. Recent advance of polyelectrolyte hydrogels in tissue engineering and regenerative medicine for drug delivery, skin healing, bone regeneration, cardiac tissue repair and anti-biofouling coating are also highlighted.

One Reagent with Two Functions: Simultaneous Living Radical Polymerization and Chain-End Substitution for Tailoring Polymer Dispersity.

The molecular weight distribution of polymer, termed dispersity (), is a fundamental parameter that determines polymer properties. Sodium azide (NaN) functions as a catalyst in organocatalyzed living radical polymerization when the reaction medium is nonpolar. In contrast, NaN can act as a nucleophile when the reaction medium is polar.

Flexible polymeric patch based nanotherapeutics against non-cancer therapy.

Flexible polymeric patches find widespread applications in biomedicine because of their biological and tunable features including excellent patient compliance, superior biocompatibility and biodegradation, as well as high loading capability and permeability of drug. Such polymeric patches are classified into microneedles (MNs), hydrogel, microcapsule, microsphere and fiber depending on the formed morphology. The combination of nanomaterials with polymeric patches allows for improved advantages of increased curative efficacy and lowered systemic toxicity, promoting on-demand and regulated drug administration, thus providing the great potential to their clinic translation.

Air-Tolerant Reversible Complexation Mediated Polymerization (RCMP) Using Aldehyde.

An air-tolerant reversible complexation mediated polymerization (RCMP) technique, which can be carried out without prior deoxygenation, is developed. The system contains a monomer, an alkyl iodide initiating dormant species, air (oxygen), an aldehyde, N-hydroxyphthalimide (NHPI), and a base. Oxygen is consumed via the NHPI-catalyzed conversion of the aldehyde (RCHO) to a carboxylic acid (RCOOH).

Current Research Trends and Perspectives on Solid-State Nanomaterials in Hydrogen Storage.

Hydrogen energy, with environment amicable, renewable, efficiency, and cost-effective advantages, is the future mainstream substitution of fossil-based fuel. However, the extremely low volumetric density gives rise to the main challenge in hydrogen storage, and therefore, exploring effective storage techniques is key hurdles that need to be crossed to accomplish the sustainable hydrogen economy. Hydrogen physically or chemically stored into nanomaterials in the solid-state is a desirable prospect for effective large-scale hydrogen storage, which has exhibited great potentials for applications in both reversible onboard storage and regenerable off-board storage applications.

Multistimuli Responsive Reversible Cross-Linking-Decross-Linking of Concentrated Polymer Brushes.

Poly(furfuryl methacrylate) (PFMA) brushes were cross-linked using bismaleimide cross-linkers via the Diels-Alder (DA) reaction at 70 °C, generating cross-linked PFMA brushes (PFMA brush gels). The cross-linked PFMA brushes were decross-linked at 110 °C via the retro-Diels-Alder (rDA) reaction, offering the temperature-responsive reversible PFMA brush gels. The wettability of the brush was tunable by cross-linking and decross-linking.

Solid-Phase Radical Polymerization of Halogen-Bond-Based Crystals and Applications to Pre-Shaped Polymer Materials.

Liquid vinyl monomers were converted into solid crystals via halogen bonding. They underwent solid-phase radical polymerizations through heating at 40 °C or ultraviolet photo-irradiation (365 nm). The X-ray crystallography analysis showed the high degree of monomer alignment in the crystals.

Metal-Free Fast Azidation by Using Tetrabutylammonium Azide: Effective Synthesis of Alkyl Azides and Well-Defined Azido-End Polymethacrylates.

An effective method to synthesize azido-end polymethacrylates from tetrabutylammonium azide (BNN ) in a nonpolar solvent (toluene) was developed. Several low-mass alkyl halides were reacted with BNN in toluene as model reactions and the rate constants of these reactions were determined, to confirm fast BNN azidation for tertiary and secondary halides. The end-group transformation of halide-end polymethacrylates was effective and nearly quantitative.

Effective Synthesis of Patterned Polymer Brushes with Tailored Multiple Graft Densities.

This paper reports an effective method to prepare patterned polymer brushes on surfaces with tailored graft densities. High-density (concentrated), moderate-density (semidiluted), and low-density (diluted) polymer brushes were fabricated in patterned manners, offering defined three-dimensional patterned structures. This method uses a middle/near-UV (≥250 nm) lamp and needs only a short time (≤10 min) to fabricate prepatterns of the initiator, in sharp contrast to the previous high-energy lithography and time-consuming processes.

Polymer Dispersity Control by Organocatalyzed Living Radical Polymerization.

Molecular weight distribution of polymers, termed dispersity (Đ), is a fundamental parameter for determining polymer material properties. This paper reports a novel approach for controlling Đ by exploiting a temperature-selective radical generation in organocatalyzed living radical polymerization. The polymers with tailored Đ were synthesized in a batch system without the assistance of an external pump.

Photo-selective chain end transformation of polyacrylate-iodide using cysteamine and its application to facile single-step preparation of patterned polymer brushes.

Cysteamine, which is an inexpensive and non-toxic aminothiol, was successfully employed as a photo-selective chain end transformation agent of iodo-terminated polymer chains (polymer-I). Polymer-I was selectively transformed to hydrogen-terminated (polymer-H) and thiol-terminated (polymer-SH) polymers with and without UV irradiation, respectively. This method is applicable to acrylate polymers.

Facile Fabrication of Concentrated Polymer Brushes with Complex Patterning by Photocontrolled Organocatalyzed Living Radical Polymerization.

Photocontrolled surface-initiated reversible complexation mediated polymerization (photo-SI-RCMP) was successfully applied to fabricate concentrated polymer brushes with complex patterning structures. Positive-type patterned polymer brushes were obtained by photo-SI-RCMP under visible light (550(±50) nm) using photomasks. A particularly interesting finding was that negative-type patterned polymer brushes were also obtainable in a facile manner.

Biocompatible Choline Iodide Catalysts for Green Living Radical Polymerization of Functional Polymers.

Herein, nontoxic and metabolizable choline iodide analogues, including choline iodide, acetylcholine iodide, and butyrylcholine iodide, were successfully utilized as novel catalysts for "green" living radical polymerization (LRP). Through the combination of several green solvents (ethyl lactate, ethanol, and water), this green LRP process yielded low-polydispersity hydrophobic, hydrophilic, zwitterionic, and water-soluble biocompatible polymethacrylates and polyacrylates with high monomer conversions. Well-defined hydrophobic-hydrophilic and hydrophilic-hydrophilic block copolymers were also synthesized.

Temperature-Selective Dual Radical Generation from Alkyl Diiodide: Applications to Synthesis of Asymmetric CABC Multi-Block Copolymers and Their Unique Assembly Structures.

Temperature-selective radical generation from a newly designed alkyl diiodide (I-R -R -I) was studied. R -I and I-R had different reactivities for generating alkyl radicals in the presence of a tetraoctylammonium iodide (ONI) catalyst. Taking advantage of the temperature selectivity, we used the alkyl diiodide as a dual initiator in ONI-catalyzed living radical polymerization to uniquely synthesize CABC non-symmetric multi-block copolymers.

Solvent-Selective Reactions of Alkyl Iodide with Sodium Azide for Radical Generation and Azide Substitution and Their Application to One-Pot Synthesis of Chain-End-Functionalized Polymers.

Herein, a new reaction of an alkyl iodide (R-I) with an azide anion (N) to reversibly generate the corresponding alkyl radical (R) is reported. Via this new reaction, N was used as an efficient catalyst in living radical polymerization, yielding a well-defined polymer-iodide. A particularly interesting finding was the solvent selectivity of this reaction; namely, R-I and N generated R in nonpolar solvents, while the substitution product R-N was generated in polar solvents.

Synthesis of Highly Reactive Polymer Nitrile -Oxides for Effective Solvent-Free Grafting.

A one-pot synthesis of polymer nitrile -oxides was achieved via the Michael addition of living polymer anions derived from vinyl monomers to commercially available -β-nitrostyrene and subsequent dehydration with concd HSO. The polymer nitrile -oxides are effective as grafting agents in catalyst- and solvent-free 1,3-dipolar cycloadditions to unsaturated-bond-containing polymers with high conversion and exhibit higher reactivity compared to that of nitrile -oxides prepared from 1,1-diphenylnitroethene. Application to the preparation of a functional glass surface was demonstrated using PBMA nitrile -oxide as a grafting agent.

Polymer nitrile N-oxides directed toward catalyst- and solvent-free click grafting.

A general method for the one-pot synthesis of stable polymer nitrile N-oxides was developed by a combination of 1,1-diphenylnitroethene with a living anionic polymer. The polymer nitrile N-oxide served as a facile and effective grafting tool for use with polymers containing unsaturated bonds in a catalyst-free and solvent-free [2+3] cycloaddition.