Macromolecular Rapid Communications

POLYOLEFINS: Controlling Polyolefin Properties by In-Reactor Blending: 3. Mechanical Properties

2013-04-18T00:00:00+02:00

Martin Ruff,* Reinhold W. Lang, Christian Paulik

The effects of multi-stage (slurry) polymerization on mechanical properties of in-reactor blended UHMW-PE materials is presented, and it is shown that due to a controlled polymerized particle morphology, mechanical properties, such as impact properties can be regulated.

Macromol. React. Eng. DOI: 10.1002/mren.201200077

Other contributions to the article series on "Polyolefins - Catalyst and Process Innovations" can be found here.

Functional Polymers: ZnII Bisterpyridine Metallopolymers: Improved Processability by the Introduction of Polymeric Side Chains

2013-04-03T00:00:00+02:00

Andreas Wild, Anke Teichler, Christian von der Ehe, Andreas Winter, Martin D. Hager, Bing Yao, Baohua Zhang, Zhiyuan Xie, Wai-Yeung Wong,* Ulrich S. Schubert*

Tailoring of the optical and mechanical properties of bisterpyridine coordination polymers is enabled by the introduction of well-defined polymeric side chains. The resulting metallopolymers exhibit improved solubility and processability and can, therefore, easily be inkjet-printed. The photophysical properties of the so-produced homogeneous films are investigated and a proof-of-principle polymer light-emitting device can be constructed.

Macromol. Chem. Phys., DOI: 10.1002/macp.201300003

Other contributions to the special series on functional polymers can be found here.

TALENT: Non-Natural Amino Acids for Protein Engineering and New Protein Chemistries

2013-03-19T00:10:00+01:00

Inchan Kwon,* Sung In Lim

Two distinct strategies, residue-specific and site-specific incorporation, allow biosynthesis of a protein containing non-natural amino acids. Non-natural amino acids introduced into a protein can be used to manipulate spectral and catalytic properties of a protein and provide new protein chemistries for bioconjugation with versatile molecules.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200710

More information on the invited Talent, Trend, and Highlight articles in Macromolecular Chemistry and Physics can be found here.

POLYOLEFINS: Analysis of Slurry-Phase Co-Polymerization of Ethylene and 1-Butene by Ziegler–Natta Catalysts Part 1: Experimental Activity Profiles

2013-03-19T00:00:00+01:00

John T. McCoy, Joao B. P. Soares, Randhir Rawatlal*

The activity of Ziegler–Natta catalysts for ethylene polymerization is studied, and a method developed to extract meaningful kinetic parameters from experimental data. Four model parameters are required to reproduce polymerization rate profiles for a range of laboratory experimental conditions.

Macromol. React. Eng. DOI: 10.1002/mren.201200078

Other contributions to the article series on "Polyolefins - Catalyst and Process Innovations" can be found here.

TREND: MAPLE Deposition of Macromolecules

2013-02-07T00:00:00+01:00

Kimberly B. Shepard, Rodney D. Priestley*

Matrix-assisted pulsed laser evaporation (MAPLE) is used to deposit thin films of a vast range of macromolecules, including polymers, proteins, and composite materials. The numerous advantages of MAPLE are discussed, and recent reports of MAPLE-deposited films for electronic and medical applications are highlighted.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200621

More information on the invited Talent, Trend, and Highlight articles in Macromolecular Chemistry and Physics can be found here.

Functional Polymers: Morphology and Field-Effect Transistor Characteristics of Electrospun Nanofibers Prepared From Crystalline Poly(3-hexylthiophene) and Polyacrylate Blends

2013-01-31T00:00:00+01:00

Chih-Chieh Chou, Hung-Chin Wu, Chih-Jung Lin, Ebrahim Ghelichkhani, Wen-Chang Chen*

Nanofiber field-effect transistors (FETs) based on crystalline poly(3-hexylthiophene) (P3HT) and poly(stearyl acrylates) (PSA) or poly(n-lauryl acrylate) (PnLA) blends are fabricated via coaxial electrospinning (ES). The maximum FET mobility is obtained for P3HT/PSA (1:0.2) blends. The crystalline PSA promotes the larger crystallinity of P3HT in the ES nanofibers, which subsequently leads to the observation of higher mobility and improves the air stability.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200580

Other contributions to the special series on functional polymers can be found here.

Functional Polymers: Thermochromic and Photovoltaic Properties of an Alternating Copolymer of Dithieno[3,2-b:2',3'-d]thiophene and Thieno[3,4-c]pyrrole-4,6-dione

2013-01-21T00:10:00+01:00

Zhao Li,* Patrick Malenfant, Ye Tao, Jianfu Ding*

A new alternating conjugated polymer, PDTTTPD, based on electron-rich dithieno[3,2-b:2',3'-d]thiophene (DTT) and electron-deficient thieno[3,4-c]pyrrole-4,6-dione (TPD) building block is designed and synthesized. PDTTTPD shows strong thermochromic effect in chlorobenzene solution and modest PCE of 2.1% in organic solar cell devices due to the steric hindrance induced twisting of the conjugated main chain. A general design rule is then suggested to control the main chain conformation of polymer materials for photovoltaic applications.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200468

Other contributions to the special series on functional polymers can be found here.

Functional Polymers: Accessing New DPP-Based Copolymers by Direct Heteroarylation Polymerization

2013-01-21T00:00:00+01:00

Jean-Rémi Pouliot, Lauren G. Mercier, Samuel Caron, Mario Leclerc*

The direct heteroarylation polymerization methodology was adapted for the diketopyrrolopyrrole moiety, giving rise to copolymers that were difficult to obtain from standard Stille or Suzuki couplings. These new low-bandgap polymers proved to be efficient electron-transporting materials enabling possible applications in all-plastic solar cells.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200573

Other contributions to the special series on functional polymers can be found here.

Functional Polymers: Screening of Film-Formation Qualities of Various Solvent Systems for π-Conjugated Polymers Via Combinatorial Inkjet Printing

2013-01-17T00:10:00+01:00

Anke Teichler, Jolke Perelaer, Ulrich S. Schubert*

A systematical investigation of the relationships between the choice of solvent system and the film quality of inkjet printed π-conjugated polymer films is presented. A significant influence of the boiling points of the chosen main and co-solvents is observed, leading to the identification of new solvent systems that reveal improved film qualities.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200547

Other contributions to the special series on functional polymers can be found here.

Functional Polymers: Recent Progress in Polymer White Light-Emitting Materials and Devices

2013-01-17T00:00:00+01:00

Chao Tang*, Xu-Dong Liu, Feng Liu, Xu-Liang Wang, Hui Xu, Wei Huang*

Polymer white light-emitting diodes (PWLEDs) are one of the most intensively researched topics in PLED. At present, there are two main methods to realize white emission in PLED. The one is to dope the host with different guests with different color, and the other is to prepare single white polymer by designing the molecular structure. Improving the performance of PWLED depends on the understanding of materials structure and properties, materials purification, and device engineering.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200305

Other contributions to the special series on functional polymers can be found here.

TREND: Recent Trends in the Chemistry of Shape-Memory Polymers

2013-01-03T00:00:00+01:00

Konstanze K. Julich-Gruner, Candy Löwenberg, Axel T. Neffe, Marc Behl, Andreas Lendlein*

Shape-memory polymers (SMPs) are stimuli-sensitive materials capable of performing complex movements on demand. This trend article highlights current approaches in the chemistry of SMPs (e.g., tailoring segment chemistry to integrate additional functions). It is illustrated that SMPs can be constructed on the molecular level as a modular system of different building blocks and netpoints.

Macromol. Chem. Phys., DOI: 10.1002/macp.201200607

More information on the invited Talent, Trend, and Highlight articles in Macromolecular Chemistry and Physics can be found here.

Polymer Conjugates: A Plethora of Block Copolypeptides

2012-03-15T00:10:00+01:00

Gijs J. M. Habraken, Andreas Heise, and Paul D. Thornton*

While natural polypeptides with a specific sequence of amino acid constituents adopt structural motifs such as α-helices, β-sheets, and random coils through non-covalent interactions, the occurrence of these features in synthetic polymers is rare. However, extended (homo)polypeptides consisting of a limited number of amino acids that lack a specific sequence can be created by N-carboxyanhydride ring-opening polymerization (NCA ROP) as a synthetically straightforward methodology to afford polypeptidic materials that may adopt secondary structures analogous to those of natural proteins. Such structures may offer biocompatibility in addition to stimuli-responsive and self-assembly properties. Paul D. Thornton and co-workers from Dublin City University offer an insight into contemporary synthetic approaches toward NCA ROP before highlighting a number of block copolypeptide architectures.

Macromol. Rapid Commun., DOI: 10.1002/marc.201100730

Polymer Conjugates: Molecular Bottlebrushes with Polypeptide Backbone

2012-03-15T00:00:00+01:00

Yu Liu, Ping Chen, and Zhibo Li*

Molecular bottlebrushes display unique macromolecular architectures with interesting properties and potential applications. Molecular bottlebrushes with polypeptides are of particular interest because they synthetically mimic natural proteoglycan. It is a challenging task to make well-defined polypeptide bottlebrush with tunable and variable side chain. Zhibo Li and co-workers (Institute of Chemistry, Chinese Academy of Sciences, Beijing) report the design and synthesis of molecular bottlebrush bearing poly-L-lysine as a backbone. A new bromo-functionalized homopolypeptide is synthesized via ring-opening polymerization, which is then used as an efficient macroinitiator for atom transfer radical polymerization of side chains to give well-defined polypeptide bottlebrushes.

Macromol. Rapid Commun., DOI: 10.1002/marc.201100649

Polymer Conjugates: 3D Arrangement of Short DNA Oligonucleotides at Surfaces

2011-10-07T00:00:00+02:00

Olivier Y. F. Henry,* Ahmed D. Mehdi, Sinead Kirwan, Josep Luis Acero Sanchez, and Ciara K. O'Sullivan*

The need for new approaches to realize rapid and highly sensitive diagnostic devices and environmental monitoring systems requires ever more effective surface chemistries. The arrangement of short DNA oligonucleotides at surfaces plays a major role in the overall surface binding capacity of the complementary sequence present in a sample. Henry, O'Sullivan and co-workers incorporate short DNA oligonucleotide into acrylamide brushes via surface initiated ATRP in an attempt to increase the DNA surface density by building 3D molecular architectures. The morphology and the performance of the resulting polymer are characterized by surface plasmon resonance and ATR-FTIR spectroscopy, as well as MALDI-TOF analysis, and compared to monolayers of thiolated DNA strands. This new approach offers a promising alternative to SAM-based nucleic acid and aptamer sensors and could enable the realization of more complex soft materials of controlled architecture capable of both recognition and signaling by including additional optically or electrochemically active moieties.

Macromol. Rapid Commun., DOI: 10.1002/marc.201100317

Polymer Conjugates: Grafting-from and RAFT Polymerization - A Powerful Combination

2011-01-25T00:00:00+01:00

Ming Li, Hongmei Li, Priyadarsi De, and Brent S. Sumerlin*

Modification of biomacromolecules with synthetic polymers is an effective means to enhance the solubility, biocompatibility, stability and activity of proteins, nucleic acids, and polysaccharides, potentially enabling a variety of new biotechnology applications. The group of Brent Sumerlin (Dallas, USA) presents the first example of combining the grafting-from and RAFT technique, providing a new method for the preparation of block copolymer polymer-protein conjugates. The resulting conjugates prepared by two consecutive grafting-from reactions via RAFT polymerization exhibit thermoresponsive behavior due to the temperature-sensitivity of the PNIPAM block.
This article is addtionally featured on MaterialsViews.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000619

Polymer Conjugates: Amine-Reactive PEGylated Nanoparticles for Potential Bioconjugation

2010-12-09T00:00:00+01:00

Guillaume Delaittre,* Gemma Justribo-Hernandez, Roeland J. M. Nolte, and Jeroen J. L. M. Cornelissen*

Functionalization of the surface of nanoparticles (NPs) is a highly important field, especially regarding their application as transport agents in drug delivery systems. Amongst others, a suitable way to obtain polymeric NPs is through the self-assembly of amphiphilic block copolymers. If the watersoluble block contains a specific moiety then the NPs will also be functionalized on their surface. Guillaume Delaittre, Jeroen Cornelissen and co-workers have developed a route towards amine-reactive polymeric NPs by using an amphiphilic block copolymer, which contains an N-hydrosuccinimidyl (NHS) ester at its water-soluble end. The reactivity of the NPs was evidenced by reacting them with primary amines, including a fluorescent dye. The activated ester remained stable throughout all synthetic steps and a nearly quantitative coupling efficiency was obtained. This work represents the first example of a PEGylated nanoparticular system with reactivity towards amines.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000365

Polymer Conjugates: Biologically Inspired Coiled Coil Linkers in Polymer-Drug Conjugates

2010-10-27T00:00:00+02:00

Bojana Apostolovic, Samuel P.E. Deacon, Ruth Duncan, and Harm-Anton Klok*

Polymer-drug conjugates are nanomedicines that consist of a water-soluble, biocompatible polymer backbone to which multiple copies of a drug molecule are bound. The linkers connecting the polymer and the drug can respond to external stimuli (pH or the presence of enzymes) and thereby trigger the release process of the drug. Harm-Anton Klok and co-workers introduced a conceptually novel class of polymer-drug conjugates in which the drug molecules are attached to the polymer via a noncovalent, so called coiled coil motif, which is formed by heterodimerization of two complementary peptide strands, one of which is attached to the polymer carrier and the other to the drug. In this study, further insight into the cell uptake and trafficking behavior of these nanomedicines is obtained using cytotoxicity and FACS experiments. The results provide important information for the design of future polymer-drug conjugates.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000434

Polymer Conjugates: A Playground for Novel Copolymers

2010-09-29T00:00:00+02:00

S. Lecommandoux* and C. Schatz*

Chemical pathways to polysaccharide block copolymers cover all the range from enzymatic polymerization to the polymerization of a synthetic block from an end-functionalized polysaccharide block (via ring-opening or radical polymerization) and to the end-to-end coupling of polysaccharide and synthetic blocks. These copolymers display physicochemical properties close to those of synthetic block copolymers and combine them with an added value in the form of biodegradability, biocompatibility, or in some cases bioactivity. Therefore, these polysaccharide conjugates might represent a new class of biomaterials for diagnosis tests, vaccine formulations, and also for the design of drug delivery systems with targeting properties. S. Lecommandoux and C. Schatz (Bordeaux, France) provide with their timely review an excellent addition to the literature on sugar-based polymers that will definitively constitute an important resource for the scientific community working in the field

Macromol. Rapid Commun., DOI: 10.1002/marc.201000267

Polymer Conjugates: How to Purify Proteins Using Polymers

2010-08-19T00:00:00+02:00

Chien-Wen Chang, Thi H. Nguyen, and Heather D. Maynard*

Proteins are important therapeutics and essential agents to study biological processes. Critical to these applications are efficient and inexpensive methods to purify these biomolecules. Heather Maynard and co-workers (UCLA) introduce a single-step method to "pull down" or isolate proteins that contain a common genetic tag, glutathione S-transferase (GST). Glutathione (GSH, a natural reductant found in living cells) reversibly interacts with GST via precise molecular recognition in aqueous solution. The researcher synthesized a pyridyl disulfide-poly(N-isopropylacrylamide) (pNIPAAm) that could be conjugated to GSH with high efficiency (95% in 30 minutes). GST was successfully thermoprecipitated upon heating the GSH–pNIPAAm above the lower critical solution temperature. Due to its simplicity and high efficiency, this method holds great potential for large-scale purification of GST-tagged proteins.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000333

Polymer Conjugates: Studying Controlled Release from Liposomes Using Polymer-Enzyme Conjugates

2010-08-18T00:00:00+02:00

Elaine L. Ferguson,* Edoardo De Luca, Richard K. Heenan, Stephen M. King, and Peter C. Griffiths*

Liposomes (vesicles) are advanced drug delivery systems and as such increasingly being used to improve the therapeutic profile of conventional chemotherapy drugs. Polymer enzyme liposome therapy (PELT) utilizes a polymer-bound enzyme to trigger the release of drugs encapsulated within a liposome. P. C. Griffith, E. L. Ferguson, and co-workers use small-angle neutron scattering (SANS) to quantify the detailed structure of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes and perturbations in that structure induced by phospholipase A2 (PLA2). They could show that the PLA2-induced hydrolysis of the DPPC – and the associated rupture of the liposome and the release of the enclosed material – may be controlled through masking with dextrin. Accordingly, the viability of using such a combinatorial nano-medicine approach as a general route for the controlled delivery of poorly soluble therapeutic molecules is demonstrated.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000241

Polymer Conjugates: Cell Receptor-Responsiveness and Targeted Delivery of Growth Factors

2010-07-08T00:00:00+02:00

Sung Hye Kim and Kristi L. Kiick*

Engineered delivery systems for bioactive signaling molecules, such as growth factors (GFs), have been extensively studied, because these vehicles provide stabilization of GF activity and prolonged delivery. Kristi Kiick's group has studied cell receptor-responsiveness and targeted delivery of the vascular endothelial growth factor (VEGF) from non-covalently assembled, heparinized polymeric hydrogels. The hydrogel is formed via specific non-covalent interactions between 4-arm star poly(ethylene glycol)-heparin and dimeric VEGF. They could show that growth factor-crosslinked hydrogels can liberate VEGF in response to specific receptors, causing gel erosion and desired cell responses, thus suggesting the potential utility of these materials in therapeutic applications, including targeted delivery.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000130

Polymer Conjugates: Bioorganic Nanoobjects of DNA Block Copolymers

2010-07-06T00:00:00+02:00

Mukhles Sowwan*, Maryam Faroun, Elad Mentovich, Imad Ibrahim, Shayma Haboush Fikri Emrah Alemdaroglu, Minseok Kwak, Shachar Richter*, and Andreas Herrmann*

Amphiphilic block copolymers comprized of organic polymers and oligonucleotides form micelles in aqueous solution due to microphase separation. These DNA block copolymer (DBC) aggregates are made of a hydrophobic polymer core and a corona of single-stranded DNA. A. Herrmann and co-workers investigate the electrical features of these bioorganic nanoobjects by doping the polymeric core of the micelles with ferrocene molecules. They could show that doping does not alter the size or shape of the micelles but significantly changes their electrical properties, as revealed by electrostatic force microscopy measurements. Their findings may lead to new possibility of using these nanoobjects in e.g. nanoelectronic and sensing applications.

Macromol. Rapid Commun., DOI: 10.1002/marc.200900904

Polymer Conjugates: Chemistry Meets Biology

2010-06-24T00:00:00+02:00

Harm-Anton Klok

Biological-synthetic polymer conjugates covalently combine one or more copies of a biomacromolecule (e.g., a peptide sequence) with one or more elements of a synthetic polymer. These hybrid materials allow the synergistical combination of the properties of these different classes of materials and serve to overcome some of their limitations. Although the first peptide-polymer conjugate was already reported in the 50s more recent advances in controlled polymerization techniques and the development of novel and improved chemoselective coupling strategies have pushed this area further ahead lately. This special series on polymer conjugates guest-edited by Harm-Anton Klok (Lausanne, Switzerland), which will publish invited articles from leading scientists, will hopefully further stimulate research in this exciting field.

Macromol. Rapid Commun., DOI: 10.1002/marc.201000182