Self-assembly of poly(2-alkyl-2-oxazoline)s by crystallization in ethanol-water mixtures below the upper critical solution temperature.

Crystallization of poly(2-isobutyl-2-oxazoline) and poly(2-nonyl-2-oxazoline) is found to occur by room temperature annealing below the upper critical solution temperature in ethanol-water solvent mixtures. Both polymers produce similar self-assembled structures (see image), resembling the previously reported crystalline hierarchical structures obtained from hot aqueous poly(2-isopropyl-2-oxazoline) solutions above the lower critical solution temperature. These observations suggest that the crystallization induced self-assembly process is a rather general phenomenon occurring for semicrystalline polymers in liquid-liquid two phase systems.

Poly(2-oxazoline)s as Smart Bioinspired Polymers.

Poly(2-alkyl-2-oxazoline)s can be regarded as pseudo-peptides or bioinspired polymers, which are available through living/controlled cationic polymerization and polymer ("click") modification procedures. Materials and solution properties may be adjusted via the nature of the side chain (hydrophilic-hydrophobic, chiral, bio-functional, etc.), opening the way to stimulus-responsive materials and complex colloidal structures in aqueous environments.

Attachment of polybutadienes to hydrogen-terminated silicon and post-derivatization of the adsorbed species.

We report the first attachment of polymers with pendant vinyl groups to hydrogen-terminated silicon(111) (Si(111)-H); 1,2-polybutadiene (M(w) = 3200-3500 g/mol) was attached to Si(111)-H under mild conditions at room temperature with visible light. We also report the partial functionalization, in solution, of 1,2-polybutadiene with various thiols using thiol-ene chemistry and the subsequent attachments of these compounds to Si(111)-H. The partially functionalized or unfunctionalized polybutadienes allow further functionalization at the surface through their unreacted carbon-carbon double bonds.

Thermo-responsive polyoxazolines with widely tuneable LCST.

The "click" modification of statistical poly[2-(isopropyl/3-butenyl)-2-oxazoline] copolymers with omega-functionalized thiols can be used to generate a toolbox of thermo-responsive polymers. The cloud points of the polymers can be finely tuned over a wide range as a function of composition and hydrophilicity of the side chain (hydrocarbon, alcohol, carboxylic acid, etc.).