Macromolecular Rapid Communications

doi: 10.1002/marc.201370056pmid: N/A

Lee, Juno; Yang, Sung Ho; Hong, Seok‐Pyo; Hong, Daewha; Lee, Haeshin; Lee, Hee‐Yoon; Kim, Yang‐Gyun; Choi, Insung S.

doi: 10.1002/marc.201370055pmid: N/A

Front Cover: The division timing of yeast cells is controlled chemically, as a step towards realization of artificial spores, by encapsulating individual yeast within polymeric multilayers of catechol‐grafted polyethyleneimine and hyaluronic acid pairs by the layer‐by‐layer technique and subsequently cross‐linking the layers. Further details can be found in the article by J. Lee, S.‐H. Yang, S.‐P. Hong, D. Hong, H. Lee, H.‐Y. Lee, Y.‐G. Kim, and I. S. Choi* on page 1351.

doi: 10.1002/marc.201370057pmid: N/A

Diegelmann, Stephen R.; Tovar, John D.

doi: 10.1002/marc.201300423pmid: 23922317

Polydiacetylenes have received intense attention on account of their well‐established chromic alterations that are detectable often by the naked eye, making them ideal for a variety of applications such as biosensory materials. These polymers have been fabricated in a variety of materials platforms including 3D crystals, 2D monolayers, and 0D spherical vesicles; however, 1D morphologies that might be useful for directional energy migration are less common. This article describes the development and current research efforts of protein‐based 1D nanowire‐like supramolecular assemblies with embedded polydiacetylenes.

Lee, Juno; Yang, Sung Ho; Hong, Seok‐Pyo; Hong, Daewha; Lee, Haeshin; Lee, Hee‐Yoon; Kim, Yang‐Gyun; Choi, Insung S.

doi: 10.1002/marc.201300444pmid: 23836762

The chemical control of cell division has attracted much attention in the areas of single cell‐based biology and high‐throughput screening platforms. A mussel‐inspired cytocompatible encapsulation method for achieving a “cell‐division control” with cross‐linked layer‐by‐layer (LbL) shells is developed. Catechol‐grafted polyethyleneimine and hyaluronic acid are chosen as polyelectrolytes for the LbL process, and the cross‐linking of polyelectrolytes is performed at pH 8.5. Cell division is controlled by the number of the LbL nanolayers and cross‐linking reaction. We also suggest a new measuring unit, t−2.0 OD 600, for quantifying “cell‐division timing” based on microbial growth kinetics.

Tominaga, Masato; Morisaki, Yasuhiro; Chujo, Yoshiki

doi: 10.1002/marc.201300368pmid: 23857676

The synthesis of novel luminescent polymer containing p‐phenylene‐ethynylene and 9,12‐linked o‐carborane units alternately in the main chain is reported. The obtained polymer exhibits intense blue photoluminescence, providing the first insights into the optical properties of a 9,12‐disubstituted o‐carborane dye. π‐Conjugated substituent at 9 and/or 12‐positions in o‐carborane is electrically independent, and both the HOMO and the LUMO levels slightly increase, whereas LUMO of the π‐conjugated substituent at 1 and/or 2‐positions in o‐carborane decrease. Thus, it is deduced that polymers consisting of the 9,12‐linked o‐carborane unit are able to be applied as light‐emitting materials.

Niu, Qun; Pan, Mingwang; Yuan, Jinfeng; Liu, Xiao; Wang, Xiaomei; Yu, Haifeng

doi: 10.1002/marc.201300431pmid: 23901006

A simple and elegant approach to fabricate anisotropic P(VC‐co‐AAEM)/PS nanoparticles with controllable morphologies via emulsifier‐free seeded emulsion polymerization is presented. Non‐cross‐linked P(VC‐co‐AAEM) seeds with hydrophilic surface are first synthesized through copolymerization of vinyl chloride (VC) and acetoacetoxyethyl methacrylate (AAEM), which are used to prepare P(VC‐co‐AAEM)/PS NPs with multiple bulges by SEP of styrene. Electron microscopy observation indicates that the content of AAEM in seeds is crucial to control the phase separation and morphology of the composite NPs. Moreover, the thermodynamic immiscibility between PVC and PS is the driving force for the formation of PS bulges onto the P(VC‐co‐AAEM) seeds. The resultant anisotropic NPs with non‐cross‐linked feature may promisingly serve as compatibilizers for further polymer processing.

Ren, Chonglei; Chen, Yu; Zhang, Haiyang; Deng, Jianping

doi: 10.1002/marc.201300342pmid: 23852622

Optically active helical substituted (co)polyacetylenes containing pendent pyrene groups are prepared and then noncovalently immobilized on graphene via π–π interactions. The resulting graphene composite is characterized by XRD, FTIR, Raman, circular dichroism, UV‐vis absorption, TEM, TGA, and fluorescent spectroscopy techniques. The helical polyacetylene endows graphene with the desired optical activity. Also interestingly, the dispersibility of the functionalized graphene in tetrahydrofuran is remarkably improved due to the presence of the helical polymer chains. The present methodology opens new opportunities and serves as a versatile platform toward preparing novel graphene‐based materials.

Castano, Marcela; Seo, Kwang Su; Kim, Eun Hye; Becker, Matthew L.; Puskas, Judit E.

doi: 10.1002/marc.201300430pmid: 23877930

Halo‐ester‐functionalized poly(ethylene glycol)s (PEGs) are successfully prepared by the transesterification of alkyl halo‐esters with PEGs using Candida antarctica lipase B (CALB) as a biocatalyst under the solventless conditions. Transesterifications of chlorine, bromine, and iodine esters with tetraethylene glycol monobenzyl ether (BzTEG) are quantitative in less than 2.5 h. The transesterification of halo‐esters with PEGs are complete in 4 h. 1H and 13C NMR spectroscopy with MALDI‐ToF and ESI mass spectrometry confirm the structure and purity of the products. This method provides a convenient and “green” process to effectively produce halo‐ester PEGs.

de Espinosa, Lucas Montero; Winkler, Matthias; Meier, Michael A. R.

doi: 10.1002/marc.201300472pmid: 23877964

Three‐ and four‐arm star shaped polymers, as well as diblock copolymers, are synthesized via acyclic diene metathesis (ADMET) polymerization. This is accomplished by using an asymmetric α,ω‐diene containing a terminal double bond and an acrylate, which is polymerized in the presence of multifunctional acrylates as selective and irreversible chain transfer agents using Hoveyda‐Grubbs second generation catalyst. High cross‐metathesis selectivities are achieved at low temperatures enabling good control over molecular weights. Furthermore, additional polyethyleneglycol (PEG) blocks are attached to these polymers via Heck coupling of the acrylate end‐groups of these polymers with aryl iodide functionalized PEG, obtaining three‐ and four‐arm star shaped di‐ and triblock copolymers with molecular weights up to 31 kDa.