Clicking polymers : a straightforward approach to novel macromolecular architectures

Living/controlled polymn. techniques have enabled the synthesis of a large variety of different well-defined (co)polymer structures. In addn., the use of click chem. in polymer science is a quickly emerging field of research since it allows the fast and simple creation of well-defined and complex polymeric structures in yields that were previously unattainable. In this crit. review, the application of the azide-alkyne 1,3-dipolar cycloaddn. for the construction of well-defined polymer architectures will be discussed in detail, providing a comprehensive overview for all disciplines related to polymeric materials. [on SciFinder (R)

Clicking polymers : a straightforward approach to novel macromolecular architectures

Living/controlled polymn. techniques have enabled the synthesis of a large variety of different well-defined (co)polymer structures. In addn., the use of click chem. in polymer science is a quickly emerging field of research since it allows the fast and simple creation of well-defined and complex polymeric structures in yields that were previously unattainable. In this crit. review, the application of the azide-alkyne 1,3-dipolar cycloaddn. for the construction of well-defined polymer architectures will be discussed in detail, providing a comprehensive overview for all disciplines related to polymeric materials. [on SciFinder (R)

Thermosensitive and switchable terpyridine-functionalized metallo-supramolecular poly(N-isopropylacrylamide)

Metallo-supramol. polymers offer attractive possibilities to combine the properties of polymers with the characteristics offered by the metal-ligand coordination. Here we present for the first time the combination of metal-bis(terpyridine) complexes and lower crit. soln. temp. (LCST) polymers that can be switched by addressing either the thermosensitive polymer or the metal complex. We describe a new strategy for the synthesis of poly(N-isopropylacrylamide) (PNIPAM) end functionalized with a terpyridine moiety, which is further used for the prepn. of FeII and ZnII-bis(terpyridine PNIPAM). The comparison of the LCST behavior of the uncomplexed ligands and their metal complexes that bear different counter ions is included. Furthermore, the switchability of the synthesized FeII system is demonstrated by a decomplexation reaction followed by the characterization of the uncomplexed ligand. [on SciFinder (R)

Synthesis and screening of polymer libraries for LCST behavior and mechanical properties

No abstract

Towards thermosensitive metallo-terpyridine supramolecular polymers

No abstrac

Thermo- and pH-responsive copolymers based on oligoethyleneglycol methacrylates

No abstract

Tunable pH- and temperature-sensitive copolymer libraries by reversible addition-fragmentation chain transfer copolymerizations of methacrylates

Reversible addn.-fragmentation chain transfer (RAFT) polymns. were performed on a Chemspeed Accelerator SLT100 automated synthesizer to polymerize N,N-(dimethylamino)ethyl methacrylate (DMAEMA) and poly(ethylene glycol) Me ether methacrylate (PEGMA) at 70 DegC. Azobis(isobutyronitrile) (AIBN) was used as source of radicals and 2-cyano-2-Bu dithiobenzoate (CBDB) as RAFT agent. A complete screening in compn. of P(DMAEMA-stat-PEGMA) copolymers was elaborated from 0% of PEGMA to 100% of PEGMA. All polydispersity indexes of the obtained copolymers are comprised between 1.11 and 1.30. The reactivity ratios were detd. by the extended Kelen-Tuedoes method (rDMAEMA = 0.93 and rPEGMA = 0.66). The behavior of the pH- and temp.-sensitive copolymers was studied in aq. soln. by measuring the lower crit. soln. temp. (LCST) by UV/vis spectroscopy. The measurements were performed at three different pH values (4, 7, and 10). At pH 7 and pH 10 the LCST is increasing linearly with the wt. % PEGMA in the copolymer feed. On the contrary, at pH 4, the hydrophilicity of the P(DMAEMA-stat-PEGMA) copolymers is too high due to the protonation of the DMAEMA units. Thus, no LCST was detected for most of them. By varying the pH and the compn. of the P(DMAEMA-stat-PEGMA) copolymers, the LCST can be easily tuned between 34.7 and 82.0 DegC

Water uptake of hydrophilic polymers determined by thermal gravimetric analyzer with a controlled humidity chamber

The moisture uptake of several water-soluble polymers at different humidities was investigated with a thermal gravimetric analyzer equipped with a controlled humidity chamber. The water sorption of poly(acrylic acid) sodium salt, poly(ethylene glycol) and silica, which are known as super absorbers, were examined. In addition, various hydrophilic polymeric materials were selected according to their structural features. These included hydroxyl functions on the side chains (e.g. poly(2-hydroxyethyl methacrylate)), as well as acidic or basic functionalities (e.g. poly (dimethylaminoethyl methacrylate) or poly(vinylimidazole)). In addition, poly(2-methyl-2-oxazoline) (P(MeOx)) and poly(2-ethyl-2-oxazoline) (P(EtOx)), which are well-known hydrophilic polymers, were also investigated in this context. More significant weight percent changes were obtained for P(MeOx) (60% at 90% relative humidity (RH)) in comparison to P(EtOx) (35% at 90% RH) as a result of the slight difference in hydrophilicity of the structures. The effect of the chain length on the ability for water uptake was also investigated for both poly(oxazolines). Finally, thermoresponsive polymers with a lower critical solution temperature (LCST) behavior (e.g. poly(N-isopropylacrylamide) and poly(dimethylaminoethyl methacrylate)) were also examined. The measurements for the latter polymers were performed below and above the LCST of each polymer whereby the humidities are varied from 0 to 90% with steps of 10%. Upon increasing humidity, the results revealed relatively high water uptake values (8% and 22% for P(NIPAM) and for P(DMAEMA), respectively) below the LCSTs of the polymers and, contrastingly, a small weight loss above their LCSTs. The present results allow a deeper insight into important structure–property relationships (e.g. the influence of the polymer backbone, functional groups, LCST behavior, etc. on the water-uptake properties), and will in subsequent steps permit the directed design of tailor-made polymers for selected applications

Water uptake of hydrophilic polymers determined by thermal gravimetric analyzer with a controlled humidity chamber

The moisture uptake of several water-soluble polymers at different humidities was investigated with a thermal gravimetric analyzer equipped with a controlled humidity chamber. The water sorption of poly(acrylic acid) sodium salt, poly(ethylene glycol) and silica, which are known as super absorbers, were examined. In addition, various hydrophilic polymeric materials were selected according to their structural features. These included hydroxyl functions on the side chains (e.g. poly(2-hydroxyethyl methacrylate)), as well as acidic or basic functionalities (e.g. poly (dimethylaminoethyl methacrylate) or poly(vinylimidazole)). In addition, poly(2-methyl-2-oxazoline) (P(MeOx)) and poly(2-ethyl-2-oxazoline) (P(EtOx)), which are well-known hydrophilic polymers, were also investigated in this context. More significant weight percent changes were obtained for P(MeOx) (60% at 90% relative humidity (RH)) in comparison to P(EtOx) (35% at 90% RH) as a result of the slight difference in hydrophilicity of the structures. The effect of the chain length on the ability for water uptake was also investigated for both poly(oxazolines). Finally, thermoresponsive polymers with a lower critical solution temperature (LCST) behavior (e.g. poly(N-isopropylacrylamide) and poly(dimethylaminoethyl methacrylate)) were also examined. The measurements for the latter polymers were performed below and above the LCST of each polymer whereby the humidities are varied from 0 to 90% with steps of 10%. Upon increasing humidity, the results revealed relatively high water uptake values (8% and 22% for P(NIPAM) and for P(DMAEMA), respectively) below the LCSTs of the polymers and, contrastingly, a small weight loss above their LCSTs. The present results allow a deeper insight into important structure–property relationships (e.g. the influence of the polymer backbone, functional groups, LCST behavior, etc. on the water-uptake properties), and will in subsequent steps permit the directed design of tailor-made polymers for selected applications