Shanghai Key Laboratory of Advanced Polymeric Materials

Shanghai, China

Shanghai Key Laboratory of Advanced Polymeric Materials

Shanghai, China
SEARCH FILTERS
Time filter
Source Type

Sun H.,State University of New York at Buffalo | Sun H.,Shanghai Key Laboratory of Advanced Polymeric Materials | Autschbach J.,State University of New York at Buffalo
ChemPhysChem | Year: 2013

Nonempirically tuned hybrid density functionals with range-separated exchange are applied to calculations of the first hyperpolarizability (β∥) and charge-transfer (CT) excitations of linear "push-pull" donor-acceptor-substituted organic molecules with extended π-conjugated bridges. An unphysical delocalization with increasing chain length in density functional calculations can be reduced significantly by enforcing an asymptotically correct exchange-correlation potential adjusted to give frontier orbital energies representing ionization potentials. The delocalization error for a number of donor-acceptor systems is quantified by calculations with fractional electron numbers and from orbital localizations. Optimally tuned hybrid variants of the PBE functional incorporating range-separated exchange can produce similar magnitudes for β ∥ as Møller-Plesset second-order perturbation (MP2) correlated calculations. Improvements are also found for CT excitation energies, with results similar to an approximate coupled-cluster model (CC2). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Sun H.,State University of New York at Buffalo | Sun H.,Shanghai Key Laboratory of Advanced Polymeric Materials | Autschbach J.,State University of New York at Buffalo
Journal of Chemical Theory and Computation | Year: 2014

In varying contexts, the terms "energy gap" (energy difference) or "band gap" may refer to different experimentally observable quantities or to calculated values that may or may not represent observable quantities. This work discusses various issues related to calculations of electronic energy gaps for organic π-conjugated oligomers and linear polymers by density functional theory (DFT). Numerical examples are provided, juxtaposing systematic versus fortuitous agreement of orbital energy gaps with observable fundamental (ionization vs electron attachment) or optical (electronic excitation) energy gaps. Successful applications of DFT using nonempirically tuned hybrid density functionals with range-separated exchange (RSE) for calculations of optical gaps, fundamental gaps, and electron attachment/detachment energies are demonstrated. The extent of "charge-transfer like" character in the longest-wavelength singlet electronic excitations is investigated. © 2014 American Chemical Society.


Wang L.,Shanghai Key Laboratory of Advanced Polymeric Materials | Lin J.,Shanghai Key Laboratory of Advanced Polymeric Materials | Zhang L.,Shanghai Key Laboratory of Advanced Polymeric Materials
Macromolecules | Year: 2010

Using real-space self-consistent field theory, we explored hierarchical microstructures selfassembled from A(BC)., multiblock copolymers. The multiblock copolymers were classified into two types in terms of relative magnitude of A/B and A/C interaction strengths: one is that XABN is less than or equal to XAC-N and the other is that XABN is greater than XACN. For both cases, the multiblock copolymers can selfassemble into hierarchically ordered microstructures with two different length scales. For XABN ≤ XACN, various hierarchical microstructures, such as cylinders-in-lamellae", lamellae-in-lamella", cylinders- incylinder", and spheres-in-sphere", were observed. In these microphases, the small-length-scale structures and the large-length-scale structures are packed in the doubly parallel forms. It was found the number of internal small-length-scale structures can be tailored by tuning the number of BC block and the interaction strength between A and BC blocks. For XABN > XACN, in addition to the parallel packed hierarchical structures, the multiblock copolymers can self-organize into perpendicular packed hierarchical structures, in which the structures with small periods are arranged perpendicular to structures with large periods. These perpendicular packed hierarchical structures were found to be only stable at higher value of XBCN. © 2010 American Chemical Society.


Wang L.,Shanghai Key Laboratory of Advanced Polymeric Materials | Lin J.,Shanghai Key Laboratory of Advanced Polymeric Materials
Soft Matter | Year: 2011

Using self-consistent field calculations, multicore micelles, such as the double-stranded superhelix, were discovered from the solution-state self-assembly of linear ABC terpolymers consisting of a solvophilic midblock and two mutually incompatible solvophobic endblocks. The multicore micelles were formed when the A and C endblocks self-associated into multiple incompatible solvophobic cores that were subdivided alternately by solvophilic B domains, thereby constructing hierarchical packing. The structures emerged depended on the relative lengths of the blocks and the solubility of the midblocks. According to the calculation results, diagrams of the observed structures as a function of the block length and midblock solubility were constructed. The results obtained can enrich our existing knowledge of the hierarchical assembly of copolymers and provide useful information for mimicking complex biological systems. © The Royal Society of Chemistry 2011.


Zhu W.,Shanghai Key Laboratory of Advanced Polymeric Materials | Lin J.,Shanghai Key Laboratory of Advanced Polymeric Materials | Cai C.,Shanghai Key Laboratory of Advanced Polymeric Materials
Journal of Materials Chemistry | Year: 2012

CaCO 3 crystallization behavior was studied in the presence of a thermo-responsive polypeptide copolymer, poly(N-isopropyl acrylamide)-b-poly(l- glutamic acid) (PNIPAM-b-PLGA). At lower temperatures, the copolymer dissolved well and the unimers mediated the formation of rosette-like calcite crystals through a mesoscale assembly process. At higher temperatures, the copolymer self-assembled into micelles with PNIPAM as the core and PLGA as the shell. The micelles mediated the formation of coral-like aragonite fiber clusters at a high micelle concentration, while fewer aragonite fibers were generated at a low concentration and vaterite crystals were obtained instead of aragonite. The time-resolved experiment revealed that the aragonite fibers were formed through a solution-precursor-solid (SPS) process via a transient polymer-induced liquid-precursor (PILP) phase. The new findings through the experiments can enrich our existing knowledge of biomimetic mineralization and provide useful information for designing functional materials. © 2012 The Royal Society of Chemistry.


Xia F.,Shanghai Key Laboratory of Advanced Polymeric Materials | Xu S.A.,Shanghai Key Laboratory of Advanced Polymeric Materials
Applied Surface Science | Year: 2013

The surface of aluminum foil was treated using silane coupling agent and chromate-phosphate conversion solution respectively, then a flexible laminate consisting of five layers was prepared using polypropylene film as inner sealant layer and epoxy resin as adhesive between polypropylene film and aluminum foil. The surface morphology and composition of the foil after treatment were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and the hydrophilicity of the foil was evaluated by contact angle measurement (CAM). The adhesive strength between the aluminum foil and polypropylene film, and the heat sealing strength of polypropylene film were measured by tensile tester, their dependences on the surface treatments were further investigated. It can be concluded that the adhesive strength and heat sealing strength depend on not only the hydrophilicity, but also the morphology of the foil surface. The rough and porous surface of the treated foil can enhance both the adhesive strength and heat sealing strength. © 2012 Elsevier B.V.


Shen J.,Shanghai Key Laboratory of Advanced Polymeric Materials | Yang C.,Shanghai Key Laboratory of Advanced Polymeric Materials | Li X.,Shanghai Key Laboratory of Advanced Polymeric Materials | Wang G.,Shanghai Key Laboratory of Advanced Polymeric Materials
ACS Applied Materials and Interfaces | Year: 2013

Hierarchical sulfonated graphene nanosheet/carboxylated multiwalled carbon nanotube/polyaniline (sGNS/cMWCNT/PANI) nanocomposites were synthesized through an interfacial polymerization method. Activated porous graphene (aGNS) was prepared by combining chemical foaming, thermal reduction, and KOH activation. Furthermore, we have successfully fabricated an asymmetric supercapacitor (ASC) using sGNS/cMWCNT/PANI and aGNS as the positive and negative electrodes, respectively. Because of its unique structure, high capacitive performance, and complementary potential window, the ASC device can be cycled reversibly at a cell voltage of 1.6 V in a 1 M H2SO4 aqueous electrolyte, delivering a high energy density of 20.5 Wh kg-1 at a power density of 25 kW kg-1. Moreover, the ASC device also exhibits a superior long cycle life with 91% retention of the initial specific capacitance after 5000 cycles. © 2013 American Chemical Society.


Xiao Y.,Shanghai Key Laboratory of Advanced Polymeric Materials | Hu A.,Shanghai Key Laboratory of Advanced Polymeric Materials
Macromolecular Rapid Communications | Year: 2011

Bergman cyclization of enediynes, regarded as a promising strategy for anticancer drugs, now finds its own niche in the area of polymer chemistry and material science. The highly reactive aromatic diradicals generated from Bergman cyclization can undergo polymerization acting as either monomers or initiators of other vinyl monomers. The former, namely homopolymerization, leads to polyphenylenes and polynaphthalenes with excellent thermal stability, good solubility, and processability. The many remarkable properties of these aromatic polymers have further endowed them to be manufactured into carbon-rich materials, e.g., glassy carbons and carbon nanotubes. Whereas used as initiators, enediynes provide a novel resource for high molecular weight polymers with narrow polydispersities. The aromatic diradicals are also useful for introducing oligomers or polymers onto pristine carbonous nanomaterials, such as carbon nano-onions and carbon nanotubes, to improve their dispersibility in organic solvents and polymer solutions. Bergman cyclization shows great promise in polymer chemistry and material science. Diradicals generated from Bergman cyclization are used for construction of soluble polyarenes, intramolecular cross-linking linear polymer chains, initiating radical polymerization and introducing polymer onto the surface of carbon materials. Recent development in these areas is highlighted. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cai C.,Shanghai Key Laboratory of Advanced Polymeric Materials | Wang L.,Shanghai Key Laboratory of Advanced Polymeric Materials | Lin J.,Shanghai Key Laboratory of Advanced Polymeric Materials
Chemical Communications | Year: 2011

Recently, increasing attention has been given to the self-assembly behavior of polypeptide-based copolymers. Polypeptides can serve as either shell-forming or core-forming blocks in the formation of various aggregates. The solubility and rigidity of polypeptide blocks have been found to have a profound effect on the self-assembly behavior of polypeptide-based copolymers. Polypeptide graft copolymers combine the advantages of a grafting strategy and the characteristics of polypeptide chains and their self-assembly behavior can be easily adjusted by choosing different polymer chains and copolymer architectures. Fabricating hierarchical structures is one of the attractive topics of self-assembly research of polypeptide copolymers. These hierarchical structures are promising for use in preparing functional materials and, thus, attract increasing attention. Computer simulations have emerged as powerful tools to investigate the self-assembly behavior of polymers, such as polypeptides. These simulations not only support the experimental results, but also provide information that cannot be directly obtained from experiments. In this feature article, recent advances in both experimental and simulation studies for the self-assembly behavior of polypeptide-based copolymers are reviewed. © 2011 The Royal Society of Chemistry.


Wang Y.,Shanghai Key Laboratory of Advanced Polymeric Materials | Hu A.,Shanghai Key Laboratory of Advanced Polymeric Materials
Journal of Materials Chemistry C | Year: 2014

Carbon quantum dots (CQDs, C-dots or CDs), which are generally small carbon nanoparticles (less than 10 nm in size) with various unique properties, have found wide use in more and more fields during the last few years. In this feature article, we describe the recent progress in the field of CQDs, focusing on their synthetic methods, size control, modification strategies, photoelectric properties, luminescent mechanism, and applications in biomedicine, optronics, catalysis and sensor issues. © the Partner Organisations 2014.

Loading Shanghai Key Laboratory of Advanced Polymeric Materials collaborators
Loading Shanghai Key Laboratory of Advanced Polymeric Materials collaborators