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You searched for: Journal Macromolecules Remove constraint Journal: Macromolecules Publication Year 2017 Remove constraint Publication Year: 2017 Source 2017 v.50 no.4 Remove constraint Source: 2017 v.50 no.4
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1. An End-Bifunctionalized Hydrophobically Modified Ethoxylated Urethane Model Polymer: Multiple Stimuli-Responsive Aggregation and Rheology in Aqueous Solution

Author:
Du, Zhukang; Ren, Biye; Chang, Xueyi; Dong, Renfeng; Tong, Zhen
Source:
Macromolecules 2017 v.50 no.4 pp. 1688-1699
ISSN:
1520-5835
Subject:
aqueous solutions; benzyl alcohol; cosmetics; hydrophobicity; irradiation; models; moieties; polymers; printers; redox reactions; rheology; urethane; viscoelasticity; viscosity
Abstract:
... Hydrophobically modified ethoxylated urethanes (HEURs) belong to an important class of telechelic associative polymers for improving solution rheological properties in many industrial fields. In this work, we describe the synthesis and solution behavior of a novel hydrophobically modified ethoxylated urethane model polymer (AzoFc-HEUR) end-bifunctionalized by Percec-type mini-dendron 3-(6-ferrocen ...
DOI:
10.1021/acs.macromol.6b02301

2. An Investigation of the Selective Chain Scission at Centered Diels–Alder Mechanophore under Ultrasonication

Author:
Duan, Han-Yi; Wang, Yu-Xiang; Wang, Li-Jun; Min, Yu-Qin; Zhang, Xing-Hong; Du, Bin-Yang
Source:
Macromolecules 2017 v.50 no.4 pp. 1353-1361
ISSN:
1520-5835
Subject:
cleavage (chemistry); cycloaddition reactions; molecular weight; nuclear magnetic resonance spectroscopy; polymers; sonication; ultrasonic treatment
Abstract:
... It is a challenging topic to disconnect a linear polymer selectively at the mechanophore site by an external force in a “cold” fashion. In this work, the effect of the power output of ultrasonication on the selective cleavage at the centered urfuryl-maleimide Diels–Alder (DA) mechanophore of poly(methyl acrylate)s (DA-PMA-a and DA-PMA-b) were quantitatively investigated by comparative study on exp ...
DOI:
10.1021/acs.macromol.6b02370

3. Antifouling Peptide Dendrimer Surface of Monodisperse Magnetic Poly(glycidyl methacrylate) Microspheres

Author:
Hlídková, Helena; Kotelnikov, Ilyia; Pop-Georgievski, Ognen; Proks, Vladimír; Horák, Daniel
Source:
Macromolecules 2017 v.50 no.4 pp. 1302-1311
ISSN:
1520-5835
Subject:
Fourier transform infrared spectroscopy; X-ray photoelectron spectroscopy; absorption; adsorption; alkynes; amino acids; bovine serum albumin; cycloaddition reactions; dendrimers; diagnostic techniques; ethylene oxide; fibrinogen; gamma-globulins; iodine; iron oxides; magnetism; medicine; microparticles; models; nanoparticles; peptides; polymerization; scanning electron microscopy; transmission electron microscopy; vaccines
Abstract:
... Antifouling properties and stability in tissue fluids are crucial for the successful application of micro- and nanoparticles in biomedicine. In this study, we prepared monodisperse magnetic poly(glycidyl methacrylate) microspheres with amino groups (mgt.PGMA-NH₂) by a multistep swelling polymerization of glycidyl methacrylate (GMA). This was followed by ammonolysis of oxirane groups and precipitat ...
DOI:
10.1021/acs.macromol.6b02545

4. Avoidance of Density Anomalies as a Structural Principle for Semicrystalline Polymers: The Importance of Chain Ends and Chain Tilt

Author:
Fritzsching, Keith J.; Mao, Kanmi; Schmidt-Rohr, Klaus
Source:
Macromolecules 2017 v.50 no.4 pp. 1521-1540
ISSN:
1520-5835
Subject:
X-radiation; crystallites; isomerization; models; molecular weight; nuclear magnetic resonance spectroscopy; polyethylene; polyethylene glycol; prediction
Abstract:
... On the basis of sufficiently realistic chain models and simulations, it is concluded that the commonly used models of the lamellar structure of melt-crystallized semicrystalline polymers unintentionally but inevitably contain layers with a higher density than in the crystallites (density anomalies). The density excess would be particularly pronounced in polymers with planar zigzag conformations in ...
DOI:
10.1021/acs.macromol.6b02000

5. Buta-1,3-diyne-Based π-Conjugated Polymers for Organic Transistors and Solar Cells

Author:
Eckstein, Brian J.; Melkonyan, Ferdinand S.; Zhou, Nanjia; Manley, Eric F.; Smith, Jeremy; Timalsina, Amod; Chang, Robert P. H.; Chen, Lin X.; Facchetti, Antonio; Marks, Tobin J.
Source:
Macromolecules 2017 v.50 no.4 pp. 1430-1441
ISSN:
1520-5835
Subject:
X-ray diffraction; additives; annealing; atomic force microscopy; molecular weight; polymers; solar cells; solubility; solubilization; spectroscopy; thermal analysis; transistors; transmission electron microscopy
Abstract:
... We report the synthesis and characterization of new alkyl-substituted 1,4-di(thiophen-2-yl)buta-1,3-diyne (R-DTB) donor building blocks, based on the −CC–CC– conjugative pathway, and their incorporation with thienyl-diketopyrrolopyrrole (R′-TDPP) acceptor units into π-conjugated PTDPP-DTB polymers (P1–P4). The solubility of the new polymers strongly depends on the DTB and DPP solubilizing (R and ...
DOI:
10.1021/acs.macromol.6b02702

6. Chain Folding in Main-Chain Liquid Crystalline Polyester with Strong π–π Interaction: An Efficient β-Nucleating Agent for Isotactic Polypropylene

Author:
Yang, Rong; Ding, Lv; Chen, Weilong; Chen, Li; Zhang, Xin; Li, Jinchun
Source:
Macromolecules 2017 v.50 no.4 pp. 1610-1617
ISSN:
1520-5835
Subject:
X-ray diffraction; crystallization; crystals; differential scanning calorimetry; light microscopy; liquids; melting; polyesters; polypropylenes; temperature; thermal properties
Abstract:
... The influence of the main-chain liquid crystalline polyester (PBDPS) on the crystallization and melting behaviors of isotactic polypropylene (iPP) has been investigated by differential scanning calorimetry (DSC), X-ray diffraction (WAXD), and polarized optical microscopy (POM). The results suggested that PBDPS is an efficient β-nucleating agent for iPP. The melting crystallization temperature as w ...
DOI:
10.1021/acs.macromol.6b02521

7. Chain-Length-Dependent Termination of Sodium Methacrylate Polymerization in Aqueous Solution Studied by SP-PLP-EPR

Author:
Kattner, Hendrik; Drawe, Patrick; Buback, Michael
Source:
Macromolecules 2017 v.50 no.4 pp. 1386-1393
ISSN:
1520-5835
Subject:
aqueous solutions; free radicals; ionization; models; polymerization; temperature; viscosity
Abstract:
... Via the single pulse–pulsed laser polymerization–electron paramagnetic resonance (SP-PLP-EPR) technique, the chain-length-dependent termination of 5 and 10 wt % sodium methacrylate (NaMAA) in aqueous solution was measured from 5 to 60 °C. The rate coefficients kₜ(i,i) for termination of two ionized radicals of identical size i were analyzed by the composite model. Three out of the four composite-m ...
DOI:
10.1021/acs.macromol.6b02641

8. Compaction of Plasmid DNA by Macromolecular Crowding

Author:
Gupta, Amar Nath; van der Maarel, Johan R. C.
Source:
Macromolecules 2017 v.50 no.4 pp. 1666-1671
ISSN:
1520-5835
Subject:
biotechnology; dextran; ionic strength; light scattering; nanoparticles; osmotic pressure; plasmids
Abstract:
... With a view to understand compaction of DNA in crowded conditions, we have measured the radius of gyration of pHSG298 plasmid (2675 bp) in its supercoiled and linear forms and in the presence of dextran nanoparticles with light scattering. It was observed that the supercoil initially expands and subsequently compacts with increasing volume fraction of the crowder. The extent of the expansion depen ...
DOI:
10.1021/acs.macromol.6b02742

9. Domain Bridging in Thermoplastic Elastomers of Star Block Copolymer

Author:
Spencer, Russell K. W.; Matsen, Mark W.
Source:
Macromolecules 2017 v.50 no.4 pp. 1681-1687
ISSN:
1520-5835
Subject:
composite polymers; mathematical theory; statistics; thermoplastics
Abstract:
... The performance of thermoplastic elastomers composed of block copolymers is dependent upon the molecular bridges linking together the discrete minority domains. Here we devise a strategy for calculating the bridging statistics for complex block copolymer architectures, using self-consistent field theory. The method is demonstrated on (AB)M stars with M identical diblock arms. The fraction of molec ...
DOI:
10.1021/acs.macromol.7b00078

10. Folding Single Chains to Single-Chain Nanoparticles via Reversible Interactions: What Size Reduction Can One Expect?

Author:
Pomposo, José A.; Rubio-Cervilla, Jon; Moreno, Angel J.; Lo Verso, Federica; Bacova, Petra; Arbe, Arantxa; Colmenero, Juan
Source:
Macromolecules 2017 v.50 no.4 pp. 1732-1739
ISSN:
1520-5835
Subject:
catalytic activity; hydrogen bonding; molecular weight; nanomedicine; nanoparticles
Abstract:
... Single-chain nanoparticles (SCNPs) constructed via reversible bonds are versatile stimuli-responsive soft nano-objects with potential use in nanomedicine, bioimaging, biosensing, and catalysis applications. In recent years, many different types of reversible SCNPs have been reported involving intrachain hydrogen bonding, host–guest interactions, and metal complex formation, among other reversible ...
DOI:
10.1021/acs.macromol.6b02427

11. Guidelines To Select the N-Heterocyclic Carbene for the Organopolymerization of Monomers with a Polar Group

Author:
Falivene, Laura; Cavallo, Luigi
Source:
Macromolecules 2017 v.50 no.4 pp. 1394-1401
ISSN:
1520-5835
Subject:
carbenes; energy; heterocyclic nitrogen compounds; zwitterions
Abstract:
... We report on the DFT stability of zwitterion and spirocycle adducts of five polar monomers with nine N-heterocyclic carbenes (NHC), covering the most typical classes of monomers and NHCs used in organopolymerization. Results indicate that the relative stability of the two adducts is dominated by the singlet–triplet energy gap of the free NHC, with low energy gaps favoring the spirocycle adduct, wh ...
DOI:
10.1021/acs.macromol.6b02646

12. Heterogeneous Morphology and Dynamics of Polyelectrolyte Brush Condensates in Trivalent Counterion Solution

Author:
Liu, Lei; Pincus, Philip A.; Hyeon, Changbong
Source:
Macromolecules 2017 v.50 no.4 pp. 1579-1588
ISSN:
1520-5835
Subject:
DNA; condensates; ions; micelles; molecular dynamics; polymers
Abstract:
... Recent experiments have shown that trivalent ion, spermidine³⁺, can provoke lateral microphase segregation in DNA brushes. Using molecular simulations and simple theoretical arguments, we explore the effects of trivalent counterions on polyelectrolyte brushes. At a proper range of grafting density, polymer size, and ion concentration, the brush polymers collapse heterogeneously into octopus-like s ...
DOI:
10.1021/acs.macromol.6b02685

13. Hydrophobic, Hydrophilic, and Amphiphilic Polyglycocarbonates with Linear and Macrocyclic Architectures from Bicyclic Glycocarbonates Derived from CO2 and Glucoside

Author:
Pati, Debasis; Feng, Xiaoshuang; Hadjichristidis, Nikos; Gnanou, Yves
Source:
Macromolecules 2017 v.50 no.4 pp. 1362-1370
ISSN:
1520-5835
Subject:
carbon dioxide; catalysts; composite polymers; glucose; glucosides; hydrophilicity; hydrophobicity; nuclear magnetic resonance spectroscopy; polymerization; triethylene glycol; zwitterions
Abstract:
... Two bicyclic glycocarbonates were synthesized in five steps from α-methyl-d-glucoside without resorting to phosgene or to its derivatives for the first time. The 4- and 6-positions of glucose were modified to introduce a six-membered carbonate ring, using CO₂ as the carbonylating reagent; the 2- and 3-positions of the same glucoside substrate were first transformed into either methyl or triethylen ...
DOI:
10.1021/acs.macromol.6b02527

14. Intermixed Donor/Acceptor Region in Conjugated Polymer Blends Visualized by Conductive Atomic Force Microscopy

Author:
Osaka, Miki; Benten, Hiroaki; Ohkita, Hideo; Ito, Shinzaburo
Source:
Macromolecules 2017 v.50 no.4 pp. 1618-1625
ISSN:
1520-5835
Subject:
annealing; atomic force microscopy; glass transition; polymers; separation; solar cells; temperature
Abstract:
... The charge-transport characteristics of phase-separated blend films of poly(3-hexylthiophene) (P3HT; electron donor) and poly[2,7-(9,9-didodecylfluorene)-alt-5,5-(4′,7′-bis(2-thienyl)-2′,1′,3′-benzothiadiazole)] (PF12TBT; electron acceptor) were visualized by conductive atomic force microscopy (C-AFM). The C-AFM hole-current images clearly showed two phases: an electrically conductive region assig ...
DOI:
10.1021/acs.macromol.6b02604

15. Interplay between Molecular Packing, Drug Loading, and Core Cross-Linking in Bottlebrush Copolymer Micelles

Author:
Unsal, Hande; Onbulak, Sebla; Calik, Filiz; Er-Rafik, Meriem; Schmutz, Marc; Sanyal, Amitav; Rzayev, Javid
Source:
Macromolecules 2017 v.50 no.4 pp. 1342-1352
ISSN:
1520-5835
Subject:
composite polymers; coumarin; crosslinking; drugs; hydrophilicity; micelles; nanoparticles; paclitaxel
Abstract:
... Amphiphilic copolymers with bottlebrush architecture provide opportunities for the refinement of materials properties that may not be attainable from their linear analogues. In this study, we investigated the effect of polymer architecture on an interplay between molecular packing inside micelle cores, cargo loading, and core cross-linking. Four families of polylactide-b-poly(ethylene oxide) (PLA– ...
DOI:
10.1021/acs.macromol.6b02182

16. Investigation of Conjugated Polymers Based on Naphtho[2,3-c]thiophene-4,9-dione in Fullerene-Based and Fullerene-Free Polymer Solar Cells

Author:
Yang, Bei; Zhang, Shaoqing; Chen, Yu; Cui, Yong; Liu, Delong; Yao, Huifeng; Zhang, Jianqi; Wei, Zhixiang; Hou, Jianhui
Source:
Macromolecules 2017 v.50 no.4 pp. 1453-1462
ISSN:
1520-5835
Subject:
dissociation; moieties; polymers; separation; solar cells
Abstract:
... Two new conjugated polymers based on the naphtho[2,3-c]thiophene-4,9-dione unit with different chemical structures but similar photoelectric properties were designed and synthesized. The differences and the related issues in their photovoltaic properties were well studied. The results show that both polymers can work well with PC₇₁BM, recording PCEs of 7.2% for PBDT-DTN and 4.9% for PIDT-DTN. Howe ...
DOI:
10.1021/acs.macromol.6b02733

17. Kinetic Monte Carlo Modeling Extracts Information on Chain Initiation and Termination from Complete PLP-SEC Traces

Author:
Marien, Yoshi W.; Van Steenberge, Paul H. M.; Barner-Kowollik, Christopher; Reyniers, Marie-Françoise; Marin, Guy B.; D’hooge, Dagmar R.
Source:
Macromolecules 2017 v.50 no.4 pp. 1371-1385
ISSN:
1520-5835
Subject:
Monte Carlo method; models; polymerization
Abstract:
... Complete pulsed laser polymerization (PLP) log-molar mass distributions (log-MMDs) are accurately simulated using kinetic Monte Carlo (kMC) modeling to gain not only knowledge on the propagation but also on the chain initiation and termination reactivity. The isothermal kMC model (306–325 K) accounts for diffusional limitations and all relevant elementary reactions, considering n-butyl acrylate, 2 ...
DOI:
10.1021/acs.macromol.6b02627

18. Linking of Ring Polymers in Slit-Like Confinement

Author:
D’Adamo, G.; Orlandini, E.; Micheletti, C.
Source:
Macromolecules 2017 v.50 no.4 pp. 1713-1718
ISSN:
1520-5835
Subject:
dispersions; mathematical theory; models; polymers; probability; topology
Abstract:
... Stochastic simulations are used to study the linking properties of solutions of circular polymers in slit confinement. Specifically, we consider dispersions of semiflexible rings at various densities ϕ and slit height, H. The competing length scales in the system have significant effects on the interchain entanglement. We observe that the linking probability is largest for a specific slit height t ...
DOI:
10.1021/acs.macromol.6b02293

19. Molecular Dynamics Simulation of the Effects of Layer Thickness and Chain Tilt on Tensile Deformation Mechanisms of Semicrystalline Polyethylene

Author:
Yeh, In-Chul; Lenhart, Joseph L.; Rutledge, Gregory C.; Andzelm, Jan W.
Source:
Macromolecules 2017 v.50 no.4 pp. 1700-1712
ISSN:
1520-5835
Subject:
crystallization; deformation; melting; molecular dynamics; polyethylene; shear stress; simulation models; stems
Abstract:
... We performed molecular dynamics simulations to investigate the effects of layer thicknesses of both crystalline and noncrystalline domains and chain tilt within the crystalline lamellae on tensile deformation mechanisms of the lamellar stack model of semicrystalline polyethylene. For equal thicknesses of crystalline and noncrystalline regions, similar stress–strain profiles were obtained with two ...
DOI:
10.1021/acs.macromol.6b01748

20. Nanoparticle Motion in Entangled Melts of Linear and Nonconcatenated Ring Polymers

Author:
Ge, Ting; Kalathi, Jagannathan T.; Halverson, Jonathan D.; Grest, Gary S.; Rubinstein, Michael
Source:
Macromolecules 2017 v.50 no.4 pp. 1749-1754
ISSN:
1520-5835
Subject:
diffusivity; melting; molecular dynamics; nanocomposites; nanoparticles; polymers; simulation models
Abstract:
... The motion of nanoparticles (NPs) in entangled melts of linear polymers and nonconcatenated ring polymers are compared by large-scale molecular dynamics simulations. The comparison provides a paradigm for the effects of polymer architecture on the dynamical coupling between NPs and polymers in nanocomposites. Strongly suppressed motion of NPs with diameter d larger than the entanglement spacing a ...
DOI:
10.1021/acs.macromol.6b02632
PubMed:
28392603
PubMed Central:
PMC5379250