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1.
Ernesto Prez Rosario Benavente María L. Cerrada Antonio Bello Jos M. Perea 《Macromolecular chemistry and physics.》2003,204(17):2155-2162
Time‐resolved synchrotron X‐ray and DSC experiments were applied to investigate the phase behaviour of poly(diethylene glycol p,p′‐bibenzoate), PDEB. The DSC results are indicative of the formation of a smectic mesophase, previously identified as a SmCA type, which can be easily quenched down to room temperature. However, the synchrotron results show that the SmCA phase undergoes some kind of ordering or transformation at temperatures below 110 °C. Moreover, the annealing of PDEB at temperatures above Tg for sufficiently long times leads to the formation of a highly ordered structure, although very thin crystals and low crystallinities are obtained.
2.
Summary: Starting in the 1960s, several kinds of photodeformable polymers have been developed, such as monolayers, polymer gels, solid films and liquid‐crystalline elastomers with different photodeformation mechanisms. This field evolved slowly until recently when significant achievements have been made. Most recently, Lendlein and co‐workers have put forward another new concept – using photo‐crosslinking to prepare deformable polymers with various pre‐determined shapes (Nature 2005 , 434, 879). This highlight gives a general introduction into photodeformable polymers and brings forth future challenges.
3.
Antoni Snchez‐Ferrer Tams Fischl Mike Stubenrauch Helmut Wurmus Martin Hoffmann Heino Finkelmann 《Macromolecular chemistry and physics.》2009,210(20):1671-1677
Photo‐crosslinkable side‐chain liquid‐crystalline polymers (LCPs) containing photoreactive benzophenone cores are synthesized in order to obtain their corresponding side‐chain liquid‐crystalline elastomers (LCEs). This strategic synthesis allows thin elastomeric films and their integration into microsystems for actuators and micromachines to be obtained. As an example of this principle, a gripper was developed. The position of its arms can be changed by applying voltages from 1.5 to 3.5 V at different rates. Small changes in the liquid‐crystalline elastomer film cause strains of up to 150% in the microdevice and the capacity to move up to 400 times its own mass due to the nematic‐to‐isotropic transformation.
4.
A general approach to construct one‐dimensional face‐to‐face alignment of porphyrin/fullerene nanowires has been developed. This system uses extended trans‐dihydroxotin(IV) porphyrin and trans‐dicarboxylate‐substituted [60]fullerenoacetic diacid compounds. The nanowires are arranged in regular one‐dimensional linear arrays with lengths in the range 50–300 nm. In the nanowires, each fullerene unit is axially coordinated to the central metal ion of a Sn(IV) porphyrin unit via Sn‐carboxylate coordination and forms a face‐to‐face aligned structure. The synthesis and the hierarchical structure of nanowires have been investigated. They could have potential applications for photoelectronic devices, organic solar cells and so on.
5.
Bunyamin Karagoz Deniz Gunes Niyazi Bicak 《Macromolecular chemistry and physics.》2010,211(18):1999-2007
Synthesis and crosslinking copolymerization of 2‐bromoethylmethacrylate in aqueous suspension is described for preparing bromoalkyl‐functional microbeads (125–420 µm). Highly transparent microspheres with a density of accessible bromoethyl groups of 1.55 mmol · g?1 were prepared in the suspension, stabilized with poly(N‐vinyl pyrrolidone), by using methyl methacrylate as diluting co‐monomer and ethylene glycol dimethacrylate as crosslinker. Bromoalkyl groups on the microparticles were employed as initiation sites for either surface‐initiated ATRP of glycidyl methacrylate or ring‐opening polymerization of 2‐methyl‐2‐oxazoline to generate epoxy‐ and N‐acetylethyleneimine‐functional hairy grafts, tethered to the particle surfaces with hydrolytically stable linkages.
6.
Jessica Gwyther Gudrun Lotze Ian Hamley Ian Manners 《Macromolecular chemistry and physics.》2011,212(2):198-201
A polystyrene‐block‐poly(ferrocenylethylmethylsilane) diblock copolymer, displaying a double‐gyroid morphology when self‐assembled in the solid state, has been prepared with a PFEMS volume fraction ?PFEMS = 0.39 and a total molecular weight of 64 000 Da by sequential living anionic polymerisation. A block copolymer with a metal‐containing block with iron and silicon in the main chain was selected due to its plasma etch resistance compared to the organic block. Self‐assembly of the diblock copolymer in the bulk showed a stable, double‐gyroid morphology as characterised by TEM. SAXS confirmed that the structure belonged to the Ia d space group.
7.
Summary: Optically pure (+) and isotactic poly[{methyl(1‐naphthyl)silylene}(o‐phenylene)methylene] terminated with methylphenylchlorosilyl was obtained by the Pt‐catalyzed ring‐opening polymerization of optically pure 1‐methyl‐1‐(1‐naphthyl)‐2,3‐benzosilacyclobut‐2‐ene in the presence of methylphenylchlorosilane as a chain transfer agent. The polymer formed was transformed into a block copolymer by reacting the terminal chlorosilyl group with a commercial poly(ethylene glycol) monomethyl ether. The formation of micelles by the block copolymer in THF‐water mixtures was investigated by fluorescence and UV. More detailed information about the aggregation of the polymer in the micelles was obtained by circular dichroism spectroscopy. It was found that dense aggregates were formed at a concentration higher than the critical micelle concentration. This concentration was higher for lower molecular weight polymer, at higher temperatures, and in more hydrophobic solvent systems. The highly aggregated structure was altered by changing the solvent system.
8.
PLLA‐MPEG diblock copolymers with a controlled number‐average molar mass ranging from 7 330 to 117 610 g · mol?1 and an L ‐lactide conversion ranging from 65.1 to 97.3% were synthesized effectively in 20 min at 100 °C by MPEG‐initiated ROP of L ‐lactide under microwave irradiation. Prolonged microwave irradiation time led to the degradation of the copolymers because the ROP reaction and the thermal degradation reaction occurred simultaneously at the later stage of the reaction process. The differential scanning calorimetric and thermogravimetric study indicated that higher melting temperatures and thermal stability were obtained for PLLA‐MPEG diblock copolymers with longer PLLA segments.
9.
Gisèle Volet Thanh‐Xuan Lav Julien Babinot Catherine Amiel 《Macromolecular chemistry and physics.》2011,212(2):118-124
CROP has been used to synthesize well‐defined POXZ with a monofunctional (iodomethane) or a bifunctional (1,3‐diiodopropane) initiator. POXZ has been functionalized with an azido group at one (α‐azido‐POXZ, = 3.58 × 103 g · mol?1) or both ends (α,ω‐azido‐POXZ, = 6.21 × 103 g · mol?1) of the macromolecular chain. The Huisgen 1,3‐dipolar cycloaddition has been investigated between azido‐POXZ and a terminal alkyne on a small or larger molecule (PEG). In each case, the click reaction has been successful and quantitative. In this way, different telechelic polymers (polymers bearing different functions such as acrylate, epoxide, or carboxylic acid) and block copolymers of POXZ and PEG have been prepared. The polymers have been characterized by means of FTIR, 1H NMR, and SEC.
10.
The mechanism of ring‐opening polymerization of some lactones and lactide initiated by lanthanum isopropoxide has been comprehensively investigated. NMR and viscosity analyses demonstrated that three active polymer chains grow per lanthanum atom and that, depending on the coordinating ability of the monomer, propagation proceeds on aggregated or unaggregated active species. It is also demonstrated that inter‐ and intramolecular side reactions are limited and that lanthanum‐based initiator selectivity in ring‐opening polymerization is analogous to that of aluminum ones.
11.
Yangjun Xia Zhicai He Junfeng Tong Bin Li Chenglong Wang Yong Cao Hongbin Wu Han Young Woo Duowang Fan 《Macromolecular chemistry and physics.》2011,212(11):1193-1201
Two narrow bandgap copolymers derived from 6,6′,12,12′‐tetraoctyl‐indeno[1,2‐b]fluorene and bithiophene or thieno[3,2‐b]thiophene‐cored benzothiadiazole are synthesized and characterized. The copolymers show broad absorption in the range 350–700 nm. The application of the copolymers as photovoltaic cells with configurations ITO/PEDOT:PSS/blend/Al and ITO/PEDOT:PSS/blend/interlayer/Al is investigated. A power conversion efficiency (PCE) of approximately 3.0% is achieved under an AM 1.5G solar simulator (80 mW cm?2) for the cells with ITO/PEDOT:PSS/polymer:PC71BM([6,6]‐phenyl‐C71 butyric acid methyl ester) (1:4)/interlayer/Al.
12.
Kai Huang Yasuteru Mawatari Masayoshi Tabata Takeyuki Sone Atsushi Miyasaka Yoshikazu Sadahiro 《Macromolecular chemistry and physics.》2004,205(6):762-770
Summary: A stereospecific polymerization of a novel aromatic acetylene containing an alkyl sulfide group, i.e., (p‐methylthiophenyl)acetylene (pMeSPA) was successfully performed to selectively give the corresponding polymer bearing a cis‐transoid structure as a main geometrical form and a very high molecular weight, = 1.7–5.8 × 106 in high yields. This was accomplished when a Rh complex catalyst, [Rh(norbornadiene)Cl]2, was used in the presence of triethylamine (TEA) solvent as a cocatalyst and its mixed solvents with TEA, together with a detailed characterization of the resulting polymers before and after compression at room temperature. Based on the data obtained before and after compression, it was concluded that compression of the PpMeSPA polymers induced a cis‐to‐trans isomerization at room temperature under vacuum even in the solid state (the Figure shows the radical generated by compression).
13.
Stphane Cuenot Sabine Gabriel Christine Jrme Robert Jrme Anne‐Sophie Duwez 《Macromolecular chemistry and physics.》2005,206(12):1216-1220
Summary: AFM‐based single‐molecule force spectroscopy was used to evaluate the mechanical strength of the link between a polymer and the substrate onto which the polymer is electrografted. Poly(N‐succinimidyl acrylate) was electrografted onto gold substrates and brought into contact with an aminothiol‐functionalized AFM tip. Bridging of single polymer chains resulting from the strong coupling between the activated esters on the polymer and amine groups on the tip was investigated. We found that the link between the polymer and the gold substrate can withstand a force far beyond the force characteristic for physisorption on gold.
14.
Biodegradable and photocurable block copolymers of ε‐caprolactone and L ‐lactide were synthesized by polycondensation of PLLA diol ( = 10 000 g · mol?1), PCL diol ( = 10 000 g · mol?1), and a chain extender bearing a coumarin group. The effect of copolymer composition on the thermal and mechanical properties of the photocured copolymers was studied by means of DSC and cyclic tensile tests. An increase in Young's modulus and a decrease in the tensile strain with increasing PLLA content was observed for the block copolymers. Block copolymers with high PCL content showed good to excellent shape‐memory properties. Random copolymers exhibited Rf and Rr values above 90% at 45 °C for an extremely large tensile strain of 1 000%.
15.
Yangjun Xia Jie Luo Xianyu Deng Xianzhen Li Dongyun Li Xuhui Zhu Wei Yang Yong Cao 《Macromolecular chemistry and physics.》2006,207(5):511-520
Summary: Novel readily soluble random low‐band‐gap conjugated copolymers (PFO–DTTP, Eg ≈ 1.77–2.00 eV) derived from 9,9‐dioctylfluorene (DOF) and 2,3‐dimethyl‐5,7‐dithien‐2‐yl‐thieno[3,4‐b]pyrazine (DTTP) were prepared. The solutions and the solid thin films of the copolymers absorbed light from 300–690 nm. Prototype photovoltaic cells from solid state composite films with the copolymer PFO–DTTP30 and [6,6]‐phenyl C61 butyric acid methyl ester (PCBM) showed power conversion efficiencies up to 0.83% under an AM1.5 solar simulator (100 mW · cm−2). For electroluminescent devices, the emission peaks were around 734–780 nm. This indicates that the low band gap copolymers are promising materials for polymeric solar cells and deep red/near infrared light‐emitting diodes.
16.
Kazuyuki Hiraoka Yoshiko Uematsu Peter Stein Heino Finkelmann 《Macromolecular chemistry and physics.》2002,203(15):2205-2210
Structural changes through successive phase transformations of a chiral smectic liquid‐crystalline elastomer are investigated by X‐ray scattering technique. In uniaxially deformed elastomers, the smectic layer seemingly tilts even in the SmA phase, in which an in‐plane chevron structure formed in the tilted smectic phase. On the basis of an analysis of the layer reflection peaks, the layer correlation length in the tilted smectic phases is shorter than that in the non‐tilted SmA phase, though smectic layers in the tilted smectic phases are better ordered than those in SmA.
17.
Dong Qiu Terence Cosgrove Andrew M. Howe 《Macromolecular chemistry and physics.》2005,206(22):2233-2238
Summary: The surfactant‐free synthesis of latex polymers of styrene and sodium styrenesulfonate (NaSS) was investigated. The development of size and size distribution of the particles was studied by photo‐correlation spectroscopy (PCS) and transmission electronic microscopy (TEM). The effects of NaSS concentration and the order of addition of reactants were examined in detail. The results showed that the particle size decreases with an increase in the styrene sulfonate concentration. The polydispersity index can be reduced by mixing NaSS with styrene homogeneously before adding initiator, but this leads to a slightly larger mean particle size.
18.
Dirk E. Heiser Jun Okuda Sandro Gambarotta Rolf Mülhaupt 《Macromolecular chemistry and physics.》2005,206(2):195-202
Summary: 1,3‐Cyclohexadiene (CHD) was homo‐ and copolymerized by means of diimine nickel complexes and various substituted titanium based half‐sandwich complexes activated with methylaluminoxane (MAO). Soluble polycyclohexadienes were produced with the constrained geometry catalyst [Me2Si(NtBu)(Me4Cp)]TiCl2 (CBT) (Cp = cyclopentadienyl, Me = methyl). Only in the presence of CBT/MAO soluble high molecular weight CHD copolymers with ethylene were obtained. The CHD incorporation was varied between 0 and 12.3 mol‐%. According to NMR analysis the CHD/ethylene copolymerization is highly regioselective, accounting for exclusive formation of 1,4‐cyclohexene units randomly distributed in the polyethylene backbone.
19.
Vaibhav Jain Hank Yochum Hong Wang Reza Montazami Mónica A. Vidales Hurtado Arturo Mendoza‐Galván Harry W. Gibson James R. Heflin 《Macromolecular chemistry and physics.》2008,209(2):150-157
A PV was synthesized by polymerization of N,N′‐bis(δ‐aminopropyl)‐4,4′‐bipyridinium bromide hydrobromide (APD) and isophthaloyl chloride (ISP). The PV was completely soluble in water as well as in organic solvents. The spectroelectrochemical and EC properties of the resulting ionic self‐assembled multilayers of PV/poly‐(2‐acrylamido‐2‐methylpropanesulfonic acid) (PAMPs) were examined by cyclic voltammetry, FT‐IR spectroscopy, UV‐vis spectroscopy, optical switching and current density measurements. Solid state devices made of PV films sandwiched with PANI as a counter electrode have switching times of 100–250 ms. 40 Bilayer films of PV/PAMPs show high contrast (ΔT = 61%) in 0.1 M NaClO4 liquid electrolyte solution and CE as high as 57 cm2 · C?1, one of the highest reported so far for any bipyridinium salt system.
20.
John E. Schwendeman Kenneth B. Wagener 《Macromolecular chemistry and physics.》2005,206(15):1461-1471
Summary: Polyethylene can be rendered completely amorphous via the insertion of regularly spaced gem‐dimethyl defects along its backbone, where frequency of insertion is the deciding factor in achieving the totally amorphous state. Accurate placement of defects along polyethylene's backbone is achieved with step polymerization metathesis chemistry (the ADMET reaction) rather than using chain polymerization techniques. These gem‐dimethyl polyethylene macromolecules, when compared with other ADMET ethylene‐based model materials, demonstrate that steric bulk, frequency, and distribution of the defect along the polymer backbone are more important than stereoregularity (tacticity) when the defects are spaced nine carbon atoms or more apart. Comparisons are made between gem‐dimethyl “defects” and methyl “defects” in a polyethylene backbone.