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Hyperbranched Copolymers (hyperbranched + copolymer)
Selected AbstractsAntifreeze Properties of Polyglycidol Block CopolymersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 23 2007Eti Baruch Abstract In this paper, we describe a new biomimetic approach to the synthesis of block copolymers with antifreeze properties. Our approach focuses on the design of block copolymers that mimic the structure and functionality of antifreeze proteins. Hyperbranched copolymers containing poly(ethylene oxide)-polyethyleneimine blocks and polyglycidol side chains were synthesized and their antifreeze properties were studied. It is shown that these block copolymers can lower the freezing point of water up to 0.8,°C at a relatively low concentration (1 mg,·,mL,1). From DSC measurements it is proven that polyglycidol block copolymers slow down the crystallization kinetics of ice and lead to changes in the ice crystal morphology, as observed by cryo-optical microscopy. [source] Hyperbranched copolymer containing triphenylamine and divinyl bipyridyl units for fluorescent chemosensorsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2009Jichang Feng Abstract A fluorescent hyperbranched copolymer (HTP) and a linear copolymer (PTP) as a reference sample to HTP both containing triphenylamine and divinyl bipyridyl units were synthesized via Heck coupling reaction from 5,5,-Divinyl-2,2,-bipyridyl with tris(4-bromophenyl)amine and with 4,4,-dibromotriphenylamie, respectively. The chemical structure of HTP was confirmed by FTIR, 1H NMR, and 13C NMR. The polymer HTP had a number-average molecular weight of 1895 and a weight-average molecular weight of 2315, and good solubility in conventional organic solvents, such as THF, DMF, and chloroform, and exhibited good thermal stability. The UV,vis absorption and photoluminescence (PL) spectra exhibited absorption maximum at 428 nm and emissive maximum at 531 nm for the HTP solution. The spectroscopic results of HTP and PTP indicated that hyperbranched conjugated structure increases the effective conjugation length, as compared with corresponding linear conjugated structure. The fluorescence of the polymer in solution can be quenched by various transition metal ions. The effect of backbone structure of the conjugated polymer-based chemosensors on the sensitivity and selectivity in metal ions sensing have been investigated, and the quenching effect of HTP is more sensitive toward transition metal than linear copolymer PTP. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 222,230, 2009 [source] Water-soluble, thermoresponsive, hyperbranched copolymers based on PEG-methacrylates: Synthesis, characterization, and LCST behaviorJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2010Mario Luzon Abstract A series of water-soluble thermoresponsive hyperbranched copoly(oligoethylene glycol)s were synthesized by copolymerization of di(ethylene glycol) methacrylate (DEG-MA) and oligo(ethylene glycol) methacrylate (OEG-MA, Mw = 475 g/mol), with ethylene glycol dimethacrylate (EGD-MA) used as the crosslinker, via reversible addition fragmentation chain transfer polymerization. Polymers were characterized by size exclusion chromatography and nuclear magnetic resonance analyses. According to the monomer composition, that is, the ratio of OEG-MA: DEG-MA: EGD-MA, the lower critical solution temperature (LCST) could be tuned from 25 °C to 90 °C. The thermoresponsive properties of these hyperbranched copolymers were studied carefully and compared with their linear analogs. It was found that molecular architecture influences thermoresponsive behavior, with a decrease of around 5,10 °C in the LCST of the hyperbranched polymers compared with the LCST of linear chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2783,2792, 2010 [source] Self-Assembly of Large Multimolecular Micelles from Hyperbranched Star CopolymersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2007Haiyan Hong Abstract This work focused on the synthesis and aqueous self-assembly of a series of novel hyperbranched star copolymers with a hyperbranched poly[3-ethyl-3-(hydroxymethyl)oxetane] (HBPO) core and many linear poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) arms. The copolymers can synchronously form unimolecular micelles (around 10 nm) and large multimolecular micelles (around 100 nm) in water at room temperature. TEM measurements have provided direct evidence that the large micelles are a kind of multimicelle aggregates (MMAs) with the basic building units of unimolecular micelles. It is the first demonstration of the self-assembly mechanism for the large multimolecular micelles generated from the solution self-assembly of hyperbranched copolymers. [source] | ||||||||||