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Macromolecular Rapid Communications

Chai-Lin Kao, Adela Ya-Ting Huang, Hui-Ting Chen
Here, this study overcomes the current barriers to efficient solid-phase synthesis of high-generation dendrimers by decreasing the loading ratio on the resin. G7 inverse poly(amidoamine) dendrimer is now prepared, for the first time, through a solid-phase synthesis using only 50% of the available reactive sites and by choosing a large resin. This preparation takes only 15 d to afford highly pure product in 80% yield with precipitation being the only purification procedure used. The results clearly show the amount of the initial monomer loaded on the resin to be a vital factor for the ability to use solid-phase synthesis to produce large dendrimers...
April 20, 2017: Macromolecular Rapid Communications
Jian Wu, Bingjie Zhang, Lifen Zhang, Zhenping Cheng, Xiulin Zhu
Iron-mediated atom transfer radical polymerization (ATRP) has gained extensive attention because of the superiority of iron catalysts, such as low toxicity, abundant reserves, and good biocompatibility. Herein, a practical iron catalyst recycling system, photoinduced iron-based water-induced phase separable catalysis ATRP with initiators for continuous activator regeneration, at room temperature is developed for the first time. In this polymerization system, the polymerization is conducted in homogenous solvents consisting of p-xylene and ethanol, using commercially available 5,10,15,20-tetraphenyl-21H,23H-porphine iron(III) chloride as the iron catalyst, ethyl 2-bromophenylacetate as the ATRP initiator, 2,4,6-trimethylbenzoyl diphenylphosphine oxide as the photoinitiator, and poly(ethylene glycol) methyl ether methacrylate as the model hydrophilic monomer...
April 19, 2017: Macromolecular Rapid Communications
Fangyuan Xie, Dan He, Han Pan, Jiaxing Jiang, Liming Ding
Two donor-acceptor copolymers based on isomeric acceptor units, [7,7'-bithieno[2',3':4,5]thieno[2,3-d]thieno[3,2-b]pyridine]-5,5'(4H,4'H)-dione (BTTP) and [2,2'-bithieno[2',3':4,5]thieno[2,3-d]thieno[3,2-b]pyridine]-5,5'(4H,4'H)-dione (iBTTP), are developed to study the effect of isomeric structures on photovoltaic performance. Compared with PBDTBTTP, PBDTiBTTP possesses a smaller bandgap for good light harvesting and a better π-π stacking for higher hole mobility. PBDTiBTTP solar cells present balanced mobilities and good nanoscale phase separation, giving a power conversion efficiency (PCE) of 6...
April 19, 2017: Macromolecular Rapid Communications
Jeroen Ter Schiphorst, Giuseppe G Melpignano, Hossein Eslami Amirabadi, Menno H J M Houben, Sterre Bakker, Jaap M J den Toonder, Albertus P H J Schenning
Microfluidic devices allow the manipulation of fluids down to the micrometer scale and are receiving a lot of attention for applications where low volumes and high throughputs are required. In these micro channels, laminar flow usually dominates, which requires long residence times of the fluids, limiting the flow speed and throughput. Here a switchable passive mixer has been developed to control mixing and to easily clean microchannels. The mixer is based on a photoresponsive spiropyran based hydrogel of which the dimensions can be tuned by changing the intensity of the light...
April 18, 2017: Macromolecular Rapid Communications
Xiaoxue Wang, Sema Ermez, Hilal Goktas, Silvija Gradečak, Karen Gleason
Novel structures comprised of GaAs nanowire arrays conformally coated with conducting polymers (poly(3,4-ethylenedioxythiophene) (PEDOT) or poly(3,4-ethylenedioxythiophene-co-3-thiophene acetic acid) display both sensitivity and selectivity to a variety of volatile organic chemicals. A key feature is room temperature operation, so that neither a heater nor the power it would consume, is required. It is a distinct difference from traditional metal oxide sensors, which typically require elevated operational temperature...
April 13, 2017: Macromolecular Rapid Communications
Dong Cui, Chen Xie, Kanyi Pu
Semiconducting polymer nanoparticles (SPNs) have evolved into a new class of photonic materials with great potential for biomedical applications. Depending on the polymer structures, SPNs can be developed into optical agents for fluorescence and chemiluminescence imaging, photosensitizers for photodynamic therapy, and heat converters for photothermal therapy. In this feature article, recent work is summarized on the development of SPNs for in vivo photoacoustic (PA) imaging, a state-of-the-art imaging modality that converts light energy into mechanical acoustic waves to provide deep tissue penetration...
April 12, 2017: Macromolecular Rapid Communications
Kevin De Bruycker, Maarten Delahaye, Pieter Cools, Johan Winne, Filip E Du Prez
Nonreactive additives are widely applied to enhance polymer properties but can leach out of the material over time. In this work, two essentially different fluorinated additives bearing a triazolinedione moiety are synthesized and grafted on several polydiene backbones (acrylonitrile-butadiene-styrene, styrene-butadiene, and styrene-isoprene-styrene (SIS) copolymers), either by dip-coating or by reaction in solution. The resulting polymers are analyzed by contact angle goniometry, size exclusion chromatography, and NMR, infrared, and X-ray photoelectron spectroscopy...
April 10, 2017: Macromolecular Rapid Communications
Fei Li, Yang Zou, Shaoyang Wang, Lei Fang, Jodie L Lutkenhaus
In this study, the authors report the highly efficient, multigram-scale synthesis of an ester-functionalized, poly(aniline-co-fluorene) polymer. The excellent solubility and film-forming ability of this polymer facilitate its application as a reversible battery cathode. Electrochemical quartz crystal microbalance with dissipation monitoring confirms a multi-electron transfer process, resulting in a specific discharge capacity of 51 mAh g(-1) and a high reversible doping level of 0.69. Galvanostatic cycling at 1 C demonstrates excellent electrode stability with a capacity retention of 95...
April 7, 2017: Macromolecular Rapid Communications
Asritha Nallapaneni, Matthew D Shawkey, Alamgir Karim
Diffuse reflectors have various applications in devices ranging from liquid crystal displays to light emitting diodes, to coatings. Herein, specular and diffuse reflectance from controlled phase separation of polymer blend films, a well-known self-organization process, are studied. Temperature-induced spinodal phase separation of polymer blend films in which one of the components is selectively extracted is shown to exhibit enhanced surface roughness as compared to unextracted films, leading to a notable increase of diffuse reflectance...
April 6, 2017: Macromolecular Rapid Communications
Heqin Huang, Yonggui Wang, Xiaojie Wang, Florian Rehfeldt, Kai Zhang
A kind of novel heterogeneous composite hydrogel with dynamic nanocrosslinkers is designed, which is built via the preorganized host-guest interaction on the surface of cellulose nanocrystals. The reversible β-cyclodextrin/adamantane conjunctions and their gradual dissociation on the nanocrystal-polymer interface guarantee the compressibility and stretchability of the composite hydrogels. While the sacrificed toughening mechanism can be rebuilt in the as-prepared hydrogels, it fails to be regenerated in the swollen hydrogels...
April 4, 2017: Macromolecular Rapid Communications
Jordan C Theriot, Blaine G McCarthy, Chern-Hooi Lim, Garret M Miyake
The recent development of organocatalyzed atom transfer radical polymerization (O-ATRP) represents a significant advancement in the field of controlled radical polymerizations. A number of classes of photoredox catalysts have been employed thus far in O-ATRP. Analysis of the proposed mechanism gives insight into the relevant photophysical and chemical properties that determine catalyst performance. Discussion of each of the classes of O-ATRP catalysts highlights their previous uses, their roles in the development of O-ATRP, and the distinctive properties that govern their polymerization behavior, leading to a set of design principles for O-ATRP catalysts...
April 3, 2017: Macromolecular Rapid Communications
Zi-Long Li, Fu-Rong Zeng, Ji-Mei Ma, Lin-Hao Sun, Zhen Zeng, Hong Jiang
Sequence-regulated polymerization is realized upon sequential cross-metathesis polymerization (CMP) and exhaustive hydrogenation to afford precision aliphatic polyesters with alternating sequences. This strategy is particularly suitable for the arrangement of well-known monomer units including glycolic acid, lactic acid, and caprolactic acid on polymer chain in a predetermined sequence. First of all, structurally asymmetric monomers bearing acrylate and α-olefin terminuses are generated in an efficient and straightforward fashion...
April 3, 2017: Macromolecular Rapid Communications
Narisu Hu, Bin Zhang, Meiyu Gai, Ce Zheng, Johannes Frueh, Qiang He
Cell transport is important to renew body functions and organs with stem cells, or to attack cancer cells with immune cells. The main hindrances of this method are the lack of understanding of cell motion as well as proper transport systems. In this publication, bubble-propelled polyelectrolyte microplates are used for controlled transport and guidance of HeLa cells. Cells survive attachment on the microplates and up to 22 min in 5% hydrogen peroxide solution. They can be guided by a magnetic field whereby increased friction of cells attached to microplates decreases the speed by 90% compared to pristine microplates...
March 31, 2017: Macromolecular Rapid Communications
Ho-Keng Lin, Ying-Ling Liu
This work demonstrates a new reactive and functional hybrid (S-MMA-POSS) of polyhedral oligomeric silsesquioxane (POSS) and sulfur prepared with a direct reaction between a multifunctional methacrylated POSS compound (MMA-POSS) and elemental sulfur (S8 ) through the "inverse vulcanization" process. S-MMA-POSS is an effective building block for imparting self-healing ability to the corresponding thermally crosslinked POSS-containing nanocomposites through a self-curing reaction and co-curing reaction with conventional thermosetting resins...
March 30, 2017: Macromolecular Rapid Communications
Daniel Moseguí González, Konstantinos N Raftopoulos, Gang He, Christine M Papadakis, Alex Brown, Eric Rivard, Peter Müller-Buschbaum
The authors study adjustable bandgap properties of the novel triple chalcogenophene-based polymer poly-(3-hexyl-2(3-(4-hexylthiophene-2-yl)-4,5-butylselenophene-1-yl)-5-(4,5-butyltellurophene-1-yl)thiophene) through a combination of morphological, spectroscopic, and computational techniques. The bandgap can be tuned after polymerization by means of mild temperature annealing, which will allow for a partnership with a broader range of donor/acceptor molecules, a property that makes it potentially suitable for organic photovoltaic implementation...
March 29, 2017: Macromolecular Rapid Communications
Raquel de la Campa, Diego García, Sandra Rodríguez, Gabino A Carriedo, Alejandro Presa Soto
The direct chemical functionalization of poly(spirophosphazene) [NP(O2 C12 H8 )]n (1) can be performed by the lithiation of the aromatic rings at low temperature using Schlosser's base (Li(t) Bu/KO(t) Bu or "superbase"), and the subsequent reaction with various electrophiles such as ClSiMe3 , ClPPh2 , or MeOB(O2 C6 H12 ) (MeOBpin). The functionalized polymers, isolated in very high yields (>90%) and without degradation of the polymeric chains, have an average degree of substitution per repeat unit ranging from 0...
March 27, 2017: Macromolecular Rapid Communications
Yixuan Song, Kevin P Meyers, Joseph Gerringer, Ramesh K Ramakrishnan, Mohammad Humood, Shuang Qin, Andreas A Polycarpou, Sergei Nazarenko, Jaime C Grunlan
A self-healable gas barrier nanocoating, which is fabricated by alternate deposition of polyethyleneimine (PEI) and polyacrylic acid (PAA) polyelectrolytes, is demonstrated in this study. This multilayer film, with high elastic modulus, high glass transition temperature, and small free volume, has been shown to be a super oxygen gas barrier. An 8-bilayer PEI/PAA multilayer assembly (≈700 nm thick) exhibits an oxygen transmission rate (OTR) undetectable to commercial instrumentation (<0.005 cc (m(-2) d(-1) atm(-1) ))...
March 27, 2017: Macromolecular Rapid Communications
Koichiro Beppu, Yuki Nagashima, Mituo Hara, Shusaku Nagano, Takahiro Seki
The microphase separation and photoalignment behavior of a diblock copolymer consisting of two kinds of side chain liquid crystalline (LC) polymers are investigated. Here, the mesogens of photoresponsive azobenzene and non-photoresponsive cyanobiphenyl are introduced in the side chains. The azobenzene and cyanobiphenyl mesogens orient homeotropically and planarly, respectively, in a thin film state. The combination of these contrasting orienting properties leads to a formation of vertically oriented lamella in the microphase separation structure...
March 24, 2017: Macromolecular Rapid Communications
Serter Luleburgaz, Meir Abuaf, Umit Tunca, Gurkan Hizal, Hakan Durmaz
l-Ascorbic acid, commonly known as vitamin C and one of the most important biological compounds, is converted to a α,ω-diene monomer and subsequently polymerized for the first time by acyclic diene metathesis. Various experimental conditions such as polymerization medium, catalyst type, temperature, and monomer/catalyst ratio are studied. The moderate molecular weight polymers are achieved when the polymerizations are conducted under bulk conditions employing the Grubbs first generation (G1) or Hoveyda-Grubbs second generation catalyst (HG-2)...
March 21, 2017: Macromolecular Rapid Communications
Yurim Shin, Chang Eun Song, Woo-Hyung Lee, Sang Kyu Lee, Won Suk Shin, In-Nam Kang
A new acceptor-donor-acceptor (A-D-A) small molecule based on benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) is synthesized via a Stille cross-coupling reaction. A highly conjugated selenophene-based side group is incorporated into each BDT unit to generate a 2D soluble small molecule (SeBDT-DPP). SeBDT-DPP thin films produce two distinct absorption peaks. The shorter wavelength absorption (400 nm) is attributed to the BDT units containing conjugated selenophene-based side groups, and the longer wavelength band is due to the intramolecular charge transfer between the BDT donor and the DPP acceptor...
March 21, 2017: Macromolecular Rapid Communications
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