Motivated by the oxygen-rich and fully amorphous structure of poly(glycidyl methyl ether) (PGME), a series of thermoresponsive poly(glycidyl methyl ether-co-ethylene oxide) copolymers P(GME-co-EO) with molecular weights in the range of 3000−20 000 g mol −1 were synthesized by the activated monomer polymerization technique. Tetraoctylammonium bromide (NOct 4 Br) was employed as an initiator in combination with triisobutylaluminum (i-Bu 3 Al) as a catalyst under mild conditions. Polyethers with varying GME content between 31 and 100 mol % were obtained. Triad sequence analysis using 13 C NMR spectroscopy proved that no pronounced block structure was obtained. Differential scanning calorimetry (DSC) revealed that samples exceeding 65 mol % content of GME are amorphous, whereas with lower GME content a low degree of crystallization was observed. Melting temperatures for these polyethers were in the range 9.8−37.5 °C. Furthermore, the copolymers' lower critical solution temperatures (LCSTs) in aqueous solution were tuned from 55 °C for the PGME homopolymer up to 98 °C by varying the amount of GME. The approach permits to combine two highly biocompatible and water-soluble materials.

No abstract

No abstract

Well-defined poly((furfuryl glycidyl ether)-co-(glycidyl methyl ether) carbonate) (P((FGE-co-GME)C)) copolymers with varying furfuryl glycidyl ether (FGE) content in the range of 26% to 100% are prepared directly from CO2 and the respective epoxides in a solvent-free synthesis. All materials are characterized by size-exclusion chromatography (SEC), (1)H NMR spectroscopy, and differential scanning calorimetry (DSC). The furfuryl-functional samples exhibit monomodal molecular weight distributions with Mw/Mn in the range of 1.16 to 1.43 and molecular weights (Mn) between 2300 and 4300 g mol(-1). Thermal properties reflect the amorphous structure of the polymers. Both post-functionalization and cross-linking are performed via Diels-Alder chemistry using maleimide derivatives, leading to reversible network formation. This transformation is shown to be thermally reversible at 110 °C.

Complex, reversible hyperbranched graft polymer topologies have been obtained by spontaneous self-assembly. Well-defined adamantyl-and β-cyclodextrin-functionalized polymers were employed to generate linear-g-(linear−hyperbranched) supramolecular graft terpolymers. For this purpose the synthesis of monoadamantyl-functionalized linear polyglycerols (Ada-linPG) and hyperbranched polyglycerols (Ada-hbPG) as well as poly(ethylene glycol)-block-linear polyglycerol (Ada-PEG-b-linPG) and poly(ethylene glycol)-block-hyperbranched poly-(glycerol) (Ada-PEG-b-hbPG) block copolymers was established. Isothermal titration calorimetry (ITC) with β-cyclodextrin revealed a shielding effect of hyperbranched polyglycerol for the adamantyl functionality, which was significantly less pronounced when using a linear spacer chain between the adamantyl residue and the hyperbranched polyglycerol block. Additionally, welldefined poly(2-hydroxypropylamide) (PHPMA) with pendant β-cyclodextrin moieties was synthesized via RAFT polymerization and sequential postpolymerization modification. Upon mixing of the β-cyclodextrin-functionalized PHPMA with Ada-PEG-b-hbPG, a supramolecular linear-g-(linear−hyperbranched) graft terpolymer was formed. The self-assembly was proven by ITC, diffusion-ordered NMR spectroscopy (DOSY), and fluorescence correlation spectroscopy (FCS).

First one-step synthesis of poly(ethylene glycol) bearing multiple alkyne-groups along the polyether backbone and subsequent generation of PEG-glycopolymers by CuAAC.

We investigate the influence of addition of hydrophilic and amphiphilic polymer on percolation behavior and micellar interactions in AOT-based water-in-oil droplet microemulsions. We focus on two series of samples having constant molar water to surfactant ratio W = 20 and constant droplet volume fraction Φ = 30%, respectively. From dielectric spectroscopy experiments, we extract the bending rigidity of the surfactant shell by percolation temperature measurements. Depending on droplet size, we find stabilization and destabilization of the surfactant shell upon addition of hydrophilic poly(ethylene glycol) (PEG) (Mn = 3100 g mol(-1)) and amphiphilic poly(styrene)-b-poly(ethylene glycol) copolymer with comparable length of the hydrophilic block. Complementary small angle X-ray scattering experiments corroborate the finding of stabilization for smaller droplets and destabilization of larger droplets. Subsequent analysis of dielectric spectra enables us to extract detailed information about micellar interactions and clustering by evaluating the dielectric high frequency shell relaxation. We interpret the observed results as a possible modification of the inter-droplet charge transfer efficiency by addition of PEG polymer, while the amphiphilic polymer shows a comparable, but dampened effect.

(1-Adamantyl)methyl glycidyl ether (AdaGE) is introduced as a versatile monomer for oxyanionic polymerization, enabling controlled incorporation of adamantyl moieties in aliphatic polyethers. Via copolymerization with ethoxyethyl glycidyl ether (EEGE) and subsequent cleavage of the acetal protection groups of EEGE, hydrophilic linear polyglycerols with an adjustable amount of pendant adamantyl moieties are obtained. The adamantyl unit permits control over thermal properties and solubility profile of these polymers (LCST). Additionally, AdaGE is utilized as a termination agent in carbanionic polymerization, affording adamantyl-terminated polymers. Using these structures as macroinitiators for the polymerization of ethylene oxide affords amphiphilic, in-chain adamantyl-functionalized block copolymers.