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Bio-based and biodegradable polymer composites, most notably poly(l-lactic acid) (PLLA) and poly(3-hydroxybutyrate) (PHB), represent a promising solution to replace conventional petroleum-based plastics. However, the brittleness and low miscibility of PLLA and PHB remain two major obstacles to practical applications. In this work, first PLLA/PHB blends are reported by melt mixing with a rigid component, poly(methyl methacrylate) (PMMA). Driven by favorable entropy, PMMA forms an interfacial nanolayer, which transforms the morphology of resultant blends. The ternary blends show 55-fold increase in elongation, 50-fold in toughness, and metal-like malleability (≈180° bending and twisting), while retaining its high stiffness (3.4 GPa) and strength (≈50 MPa). The mechanical improvement arises from numerous craze fibrils and shear deformation of the matrix, induced by the incorporated PMMA. Furthermore, this generic strategy can be applied to design other mechanically robust biocomposites for advanced green devices., (© 2021 Wiley-VCH GmbH.)

Polydopamine-derived carbon (C-PDA) nanospheres embedded with zinc ferrite (ZnFe2O4) are synthesized by in situ polymerization of dopamine with zinc and iron species followed by carbonization. The composite nanospheres contain ZnFe2O4 nanoparticles ∼8 nm in size well dispersed in porous C-PDA. The unique structure and morphology endow the nanospheres with excellent rate capability and cycling stability for use as anodes in lithium-ion batteries.

In this work, monodisperse polydopamine (PDA) spheres with tunable diameters have been synthesized through a facile and low cost method using a deionized water and alcohol mixed solvent. The PDA spheres possess surface functional groups (-OH, -NH(2)), exhibiting an extraordinary versatile active nature. It is demonstrated that the PDA spheres could serve as an active template for the convenient synthesis of various nanostructures, e.g., MnO(2) hollow spheres or PDA/Fe(3)O(4) and PDA/Ag core/shell nanostructures. No surface modification or special treatment is required for the synthesis of these nanostructures, which makes the fabrication process simple and very convenient. The novel application of PDA/Fe(3)O(4) spheres as fillers in nanocomposites for high-performance capacitors is demonstrated, indicating a promising practicality. The PDA spheres provide a new general platform not only for the facile assembly of nanostructures but also a green synthetic template for practical applications., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Thin carbonized polydopamine (C-PDA) coatings are found to have similar structures and electrical conductivities to those of multilayered graphene doped with heteroatoms. Greatly enhanced electrochemical properties are achieved with C-PDA-coated SnO(2) nanoparticles where the coating functions as a mechanical buffer layer and conducting bridge.

Polydopamine-coated graphene oxide (DGO) films exhibit electrical conductivities of 11,000 S m(-1) and 30,000 S m(-1) upon vacuum annealing at 130 °C and 180 °C, respectively. Conductive poly(vinyl alcohol)/graphene and epoxy/graphene nanocomposites show low percolation thresholds due to the excellent dispersibility of the DGO sheets and their effective in situ reduction.

Electrochromic (EC) materials and polymer electrolytes are the most imperative and active components in an electrochromic device (ECD). EC materials are able to reversibly change their light absorption properties in a certain wavelength range via redox reactions stimulated by low direct current (dc) potentials of the order of a fraction of volts to a few volts. The redox switching may result in a change in color of the EC materials owing to the generation of new or changes in absorption band in visible region, infrared or even microwave region. In ECDs the electrochromic layers need to be incorporated with supportive components such as electrical contacts and ion conducting electrolytes. The electrolytes play an indispensable role as the prime ionic conduction medium between the electrodes of the EC materials. The expected applications of the electrochromism in numerous fields such as reflective-type display and smart windows/mirrors make these materials of prime importance. In this article we have reviewed several examples from our research work as well as from other researchers' work, describing the recent advancements on the materials that exhibit visible electrochromism and polymer electrolytes for electrochromic devices. The first part of the review is centered on nanostructured inorganic and conjugated polymer-based organic-inorganic hybrid EC materials. The emphasis has been to correlate the structures, morphologies and interfacial interactions of the EC materials to their electronic and ionic properties that influence the EC properties with unique advantages. The second part illustrates the perspectives of polymer electrolytes in electrochromic applications with emphasis on poly (ethylene oxide) (PEO), poly (methyl methacrylate) (PMMA) and polyvinylidene difluoride (PVDF) based polymer electrolytes. The requirements and approaches to optimize the formulation of electrolytes for feasible electrochromic devices have been delineated., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A facile biomimetic method was developed to enhance the interfacial interaction in polymer-layered silicate nanocomposites. By mimicking mussel adhesive proteins, a monolayer of polydopamine was constructed on clay surface by a controllable coating method. The modified clay (D-clay) was incorporated into an epoxy resin, it is found that the strong interfacial interactions brought by the polydopamine benefits not only the dispersion of the D-clay in the epoxy but also the effective interfacial stress transfer, leading to greatly improved thermomechanical properties at very low inorganic loadings. Rheological and infrared spectroscopic studies show that the interfacial interactions between the D-clay and epoxy are dominated by the hydrogen bonds between the catechol-enriched polydopamine and the epoxy.

A series of conjugated polymers bearing thiophene‐based donors and pyromellitic diimide (PMDI) acceptor were prepared, and their electrochromic (EC) properties were studied via using fabricated thin‐film EC devices. It was observed that structurally regular alternating polymers with fewer (1 and 2) thiophene donors do not exhibit any EC properties while increasing the number of donors eventually led to the emergence of orange‐red‐to‐green colour switching. On this basis, two more random co‐polymers containing higher donor‐to‐acceptor ratios were synthesized to further improve EC switching properties. The two polymers, which bear a PMDI‐to‐thiophene ratio of ca. 1 : 7 and 1 : 8, revealed orange red‐to‐blue colour switching and generally improved optical contrasts and switching speeds in both the visible and near infra‐red (NIR) region. In addition, the subtle modulation of polymer colour and hue via variation of the number of thiophene donors was evident through colorimetric study. This work therefore demonstrates the potential and possibility of using the PMDI acceptor unit to construct EC‐active conjugated polymers, and considerations for future tuning of colour and switching performances. [ABSTRACT FROM AUTHOR]

A series of dithienothiophene-based electrochromic polymers are synthesized by a Stille coupling reaction of 2,6-bis(trimethylstannyl)dithieno[3,2- b:2′,3′- d]thiophene, 2,5-dibromo-3,4-bis(dodecyloxy)thiophene, and tris(4-bromophenylamine). The resulting polymers have high molecular weights in the range of 59 200 to 81 300 g mol−1, and good solubility in common organic solvents. The polymer films are purple/red in neutral states and gradually become gray when oxidized to an intermediate state and blue when fully oxidized. Incorporation of triphenylamine into the polymer chains has resulted in a significant increase in the redox stability, which renders this a potential method to create high-performance electrochromic polymers. [ABSTRACT FROM AUTHOR]

An electrofluorochromic (EFC) conjugated copolymer ( PEFC) containing carbazole and benzothiadiazole (BTD) moieties is synthesized through Suzuki coupling followed by electrochemical polymerization, resulting in a nanoporous EFC polymer electrode. The electrode exhibits high sensitivity and selectivity in the EFC detection of cyanide anions (CN−) in largely aqueous electrolyte (67 vol % water) because electrochemical oxidation of PEFC leads to significant fluorescence quenching, and the presence of different concentrations (1 to 100 μ M) of CN− in the electrolyte can weaken the oxidative quenching to substantially different extents. Although PEFC is hydrophobic in the neutral state, it is converted to radical cation/dication states upon oxidation, rendering the PEFC some hydrophilicity. Moreover, its nanoporous morphology provides a large surface area and short diffusion distance, facilitating the movement of CN− in the electrolyte into the PEFC film to interact with receptors. Density functional theory calculations show that the noncovalent interaction between electron-deficient BTD and nucleophilic CN− is energy favorable in the oxidized states in both aqueous and organic media, suggesting that the specific π−-π+ interaction plays the main role in the CN− detection. [ABSTRACT FROM AUTHOR]

High conductivity, good stability, and high transmittance in the visible region are the three essential requirements for the polymer electrodes used in the optoelectronic devices. It was found that with addition of diols, such as ethylene glycol, diethylene glycol, or poly(ethylene glycol) (PEG), to the poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) emulsion before spin-coating could increase dramatically the conductivities of the resultant PEDOT:PSS thin films from 1 to 90 S cm while maintain the optical transparency of the modified thin films. With up to −2.4 V potential applied, the PEDOT:PSS with PEG 200 additive does not show obvious color change, indicating its good electrochemical stability as polymer electrode. Detailed studies on the structures and morphologies of these modified PEDOT:PSS thin films, in comparison to that of PEDOT:PSS without additives were carried out using AFM, Raman, and FTIR to investigate the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the effects of polyimide (PI) structure on electrical conductivity of blends of dodecylbenzene sulfonic acid-doped polyaniline (PANI-DBSA) and PI, as well as its thermal degradation behavior. Four types of PIs with different molecular architecture were synthesized and subsequently solution blended with PANI-DBSA. Of the four types of PIs, 4-4′-diaminodiphenyl sulfone (DADPS)-based PI provides the highest conductivity to the blends. It is attributed to the rigid nature of DADPS, which may induce more extended conformation of PANI chains, and hence result in a more ordered structure. The conductivity of the blends has significant higher thermal stability than that of PANI-DBSA. The thermal stability is, however, independent on the polyimide structure. TGA studies show that the PI matrix may have hindered the thermo-oxidative degradation and evaporation of the dopants and thus slowed down the process of thermal degradation of the conductivity. [Copyright &y& Elsevier]

Abstract: There are increasing demands in recent years in manufacturing of polymer micro-components due to the worldwide trend slanting towards miniaturization. However, polymer materials specially tailored for micro-molding applications are yet to be developed. In the micro-molding industry selected commercial materials developed for the conventional molding applications have been used in micro-molding applications. There are limitations for many of these materials to be used successfully in practical applications because there are stringent requirements on both the material flowability and mechanical properties. The ease with which the part accuracy can be achieved is the decisive criterion for material selection in micro-molding process. To achieve desired part accuracy, materials with low melt viscosity are desirable. For many engineering plastics, the low flowability is the main drawback for their wide applications in the micro-molding process. In the present work, a new liquid crystalline polymer (LCP) based processing aid has been used to assist in micro-molding of a polycarbonate resin. It has been found that the viscosity of the PC resin can be greatly reduced by adding a small amount (2wt.%) of the processing aid. And the filling behavior of the blend has been greatly improved in the micro-molding process compared with the original resin. [Copyright &y& Elsevier]

[Display omitted] Enhancing the deposition of fragrance delivery systems contained in personal care products on target surfaces is crucial for increasing the longevity of scent, efficiently utilizing expensive functional compounds and limiting the generation of microplastics in domestic waste water. In this work, we designed and synthesized a new type of biomimetic macromolecules, chitosan- graft - L -lysine- L -DOPA (C-L-D), as a versatile biodegradable adhesion promoter to facilitate the deposition of biodegradable fragrance carriers on diverse surfaces including hair, cotton and skin. The C-L-D has hyperbranched chain architecture with many oligopeptide adhesive tentacles, each being a simple mimic of mussel adhesive proteins. It also exhibits unique amphiphilic characteristic. As a result, it could be facilely anchored on cargo-loaded poly(lactic- co -glycolic acid) nanoparticle surface via self-assembly in the particle preparation process. The C-L- D -modified nanoparticles show significantly higher deposition efficiencies than polyvinyl alcohol- and chitosan-coated particles when deposited on the target surfaces in different aqueous media as the lysine and DOPA units are capable of providing multi-noncovalent interactions, including electrostatic, polar, hydrophobic interactions, and bidentate hydrogen bonds, with the target surfaces, and possibly also inducing oxidative cross-linking. A much higher retention rate of the C-L- D -modified nanoparticles on cotton surface is also observed after washing with a soap solution, which could be attributed to the significant role played by bidentate hydrogen bonds. These findings suggest that C-L-D is a versatile biodegradable adhesion promoter and has the potential to be applied for various personal care applications and beyond. [ABSTRACT FROM AUTHOR]

Abstract: A high-contrast complementary electrochromic device based on polyaniline (PANI) tethered polyhedral oligomeric silsesquioxane (POSS) (POSS-PANI) and poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonic acid) (PEDOT:PSS) is assembled. The electrochromic properties, cyclic voltammetry behavior and coloration efficiency of the device are studied. Due to the loosely packed structure, POSS-PANI gives rise to a significantly higher electrochromic contrast, coloration efficiency and faster switching speed than PANI. Despite its high contrast, the combination of POSS-PANI with PEDOT:PSS still shows synergy in terms of contrast enhancement, which can be attributed to the additional driving force for the diffusion of dopants into PEDOT:PSS provided by the dedoping of POSS-PANI. [Copyright &y& Elsevier]

Polydopamine (PDA), a mussel-inspired adhesive polymer, has recently been explored as promising adsorbent for water purification. The adsorption ability of PDA for some pollutant species, however, decreases significantly under basic conditions because the electrostatic repulsion between negatively charged pollutants and PDA adsorbents. In this work, porous electrospun polystyrene (PS) fibers are functionalized by coating a thin layer of PDA and subsequently attaching β-cyclodextrin (β-CD) on the surface. With abundant catechol groups, the PDA layer allows facile attachment of β-CD on the fiber surface via multiple hydrogen bonds. The tailored porous morphology of the PS fibers and precisely controlled PDA coating thickness provide the functionalized fibers (β-CD/PDA/PS) large specific surface area. Furthermore, the formation of inclusion complexes and the multiple hydrogen bonds between PDA and the very weak acidic hydroxyl groups on CDs are not significantly disturbed by the high pH environments. These endow the β-CD/PDA/PS fibers much improved ability in adsorption of negatively charged pollutants under highly basic conditions than PDA-functionalized fibers. The β-CD/PDA/PS fibers can effectively remove phenolphthalein from aqueous solutions at pH = 10, and also exhibit good stability in ethanol, providing the fibers reusability. [ABSTRACT FROM AUTHOR]

In this work, graphene is facilely prepared by direct exfoliation of graphite in aqueous media with the assistance of alkali lignin (AL). The graphite is successfully exfoliated into single- and multi-layer graphene, with about 20% monolayer ones, and the concentration of graphene in the aqueous dispersions can reach 0.65 ± 0.03 mg mL −1 . The nanosheets are stabilized in the dispersions owing to π–π interaction between the graphene and AL, and the electrostatic repulsion between negative charged AL, as verified by fluorescence and zeta-potential measurements. The results also show that there are very few defects in the basil-plane of the graphene so that the free-standing graphene films prepared from the dispersions exhibit good electrical conductivity. Finally, the addition of only 0.1 wt% such graphene sheets to an epoxy resin gives 15%, 49%, and 97% enhancement in tensile strength, critical stress intensity factor and critical strain energy release rate, respectively. [ABSTRACT FROM AUTHOR]

Abstract: We report the structures, electrochemical and electrochromic properties of organic–inorganic hybrid polymers prepared via copolymerization of octa(aminophenyl) silsesquioxane and aniline. Compared with homopolyaniline (PANI), this class of novel materials exhibits much greater thermodynamic penetrability in solution, as detected using static and dynamic light scattering, suggesting that they have a star-like molecular geometry. Due to their star-like geometry, in solid state the copolymers (POSS–PANI) exhibit a loosely packed structure with relatively low crystallinity, as evidenced by X-ray and TEM characterization, and hence relatively high ionic conductivity. Cyclic voltammetric studies show that POSS–PANI undergoes similar electrochemical reactions to that of PANI but its loosely packed structure allows slightly faster cation diffusion. Spectro-electrochemical studies show a ∼40% enhancement in electrochromic contrast brought by tethering PANI onto POSS, which can be attributed to more accessible doping sites in POSS–PANI. Furthermore, the electrochemical stability of POSS–PANI is also significantly improved over that of PANI. Infrared spectroscopic measurements indicate that the formation of electrochemically inactive quinonediimine is retarded in POSS–PANI possibly due to the increased conformation freedom of the dopant anions. [Copyright &y& Elsevier]