A recyclable dynamic semiconducting polymer consisting of Pauli-paramagnetic diradicaloids promoted and stabilized by catechol-boron coordination.

Coordination between 5,5',6,6'-tetrahydroxyindigo (4OH-ID) and boron tribromide unexpectedly affords a novel dynamic covalent polymer, namely P(ID-O-B), consisting of alternating indigo and indigo diradicaloid units. The catechol-boron dynamic bond plays a vital role in promoting the diradicaloid formation and stabilizing the formed diradicaloid segments. The diradicaloid segment in the polymer has a triplet ground state and a thermally populated doublet state, which has been confirmed by the EPR study.

Tetrazaisoindigos:Serpentine Syntheses and Their Expected and Unexpected Photophysical and Electronic Properties.

Isoindigo, an electron-withdrawing building block for polymeric field-effect transistors, has long been considered to be non-fluorescent. Moreover, using electron-deficient heterocycle to replace the phenyl ring in the isoindigo core for better electron transport behaviour is synthetically challenging. Here we report the syntheses of a series of tetrazaisoindigos, including pyrazinoisoindigo (PyrII), pyrimidoisoindigo (PymII) and their hybrid (PyrPymII), and the investigation on their photophysical and electric properties.

Mussel-inspired polymeric coatings with the antifouling efficacy controlled by topologies.

Block copolymers with different topologies (linear, loop, 3-armed and 4-armed polymers) containing poly(-vinylpyrrrolidone) (PVP) antifouling blocks and terminal poly(dopamine-acrylamide) (PDAA) anchoring blocks were synthesized. These polymers can form a robust antifouling nanolayer on various surfaces. The morphologies of the polymer-modified surfaces are strongly dependent on the topologies of the polymers: with the increase of arm numbers, the morphology evolves from the smooth surface to the nanoscale coarse surface.

Fast-Curing Mussel-Inspired Adhesive Derived from Vegetable Oil.

The development of functional materials based on renewable resources is of great significance in today's resource shortage. Here, we present an effective way to synthesize a mussel-inspired adhesive from acrylated epoxidized soybean oil (AESO), a renewable and commercially available small molecular material with a molecular weight around 1200 Da, by a one-step esterification reaction with the affordable 3,4-dihydroxybenzoic acid (DHA). By taking advantages of both the double bond and the catechol moiety presented in this small molecular adhesive, a short curing time was achieved with UV irradiation.

Solvent-Induced Supramolecular Assembly of a Peptide-Tetrathiophene-Peptide Conjugate.

The assembly of a peptide-tetrathiophene-peptide (PTP) conjugate has been investigated in mixed solvents, which has different polarities by changing the solvent proportions. It was found that PTP can form fibers in THF/hexane solutions with 40-80%v of hexane. The fibers were stable and did not change on time.

A versatile platform to achieve mechanically robust mussel-inspired antifouling coatings via grafting-to approach.

Although significant progress has been made in mussel-inspired antifouling coatings, most of them suffer from low mechanical stability. Herein, we present a facile and efficient method to fabricate mechanically robust mussel-inspired antifouling coatings. A polyvinyl alcohol (PVA)-based mussel-inspired coating material, which exhibits the highest adhesion capability (always at 5B level in a tape adhesion test based on the ASTM D3359 method) and excellent anti-abrasive properties (little mass loss after 1000 abrasion cycles), is used as a universal platform for further modification to introduce antifouling properties.

Contribution of the Polarity of Mussel-Inspired Adhesives in the Realization of Strong Underwater Bonding.

Although the role of 3,4-dihydroxyphenyl--alanine(DOPA)in mussel foot proteins (mfps) in the realization of underwater bonding has been widely recognized, the role of the polarity of the polymer was largely overlooked. Here, by systematically comparing the underwater bonding properties of four mussel-inspired adhesives with different amide/lactam contents but similar catechol contents and molecular weights, we came to the conclusion that the polarity of the polymers also contributes to the strong underwater bonding. With the increase in the amide/lactam contents, the polarity of the polymeric adhesive increases, which correlates to the improved underwater bonding strength.

Robust mussel-inspired coatings for controlled zinc ion release.

Although mussel-inspired coatings have been extensively studied, most of them suffer from high-cost preparation, poor mechanical strength and low abrasion resistance, which impede them from practical applications. In this study, we report the synthesis of low-cost but robust mussel-inspired coatings based on polyvinyl alcohol (PVA), which could continuously release zinc ions at a high release rate when immersed into artificial seawater (ASW). The coating exhibits high mechanical strength, strong adhesion to stainless steel (SS), and excellent anti-abrasion properties.

Simple but Strong: A Mussel-Inspired Hot Curing Adhesive Based on Polyvinyl Alcohol Backbone.

The strong adhesion ability of mussel foot-byssal proteins (Mfps) has inspired scientists to develop novel materials for strong and reversible adhesion, coating, antifouling, and many other applications. However, in many cases, the high costs and the tedious preparation steps of such bioinspired materials hamper the process to push them into practical application. Here a simple but effective way (one step) is presented to synthesize a mussel-inspired glue from two cheap commercially available materials: polyvinyl alcohol (PVA) and 3,4-dihydroxybenzaldehyde (DBA).

A mussel-inspired adhesive with stronger bonding strength under underwater conditions than under dry conditions.

A mussel-inspired adhesive based on a polyvinylpyrrolidone (PVP) backbone shows a much higher bonding strength under underwater/seawater conditions than under dry conditions. We reasoned that besides catechol moieties, the structure and properties of the backbone also play an important role in the realization of strong underwater bonding.

Oligopeptide-assisted self-assembly of oligothiophenes: co-assembly and chirality transfer.

The biomolecule-assisted self-assembly of semiconductive molecules has been developed recently for the formation of potential bio-based functional materials. Oligopeptide-assisted self-assembly of oligothiophene through weak intermolecular interactions was investigated; specifically the self-assembly and chirality-transfer behavior of achiral oligothiophenes in the presence of an oligopeptide with a strong tendency to form β-sheets. Two kinds of oligothiophenes without (QT) or with (QTDA) carboxylic groups were selected to explore the effect of the end functional group on self-assembly and chirality transfer.

Tuning the self-assembly of oligothiophenes on chemical vapor deposition graphene: effect of functional group, solvent, and substrate.

Tuning and characterizing the interfacial structure of organic semiconductors on graphene is essential for graphene-based devices. Regulation of the supramolecular assembling structure of oligothiophenes on graphene by changing functional groups attached to the backbone of oligothiophenes is described and the assembling behavior is compared with that on the basal plane of highly oriented pyrolytic graphite. It reveals that terminal functional groups attached to the conjugated backbone of oligothiophene can entirely change the assembling structures.

Oligothiophenes on CVD graphene grown on multi-crystalline copper foil: supramolecular assembly and impact of morphology.

On graphene grown on copper foil, oligothiophenes form identical supramolecular assemblies on different copper facets. Most importantly, we found that the graphene ripple structures, even with a height as small as ~0.5 nm, can significantly alter the molecule-substrate interaction, which has never been observed previously.