Aqueous graphene dispersions-optical properties and stimuli-responsive phase transfer.

We demonstrate essentially complete exfoliation of graphene aggregates in water at concentrations up to 5% by weight (166-fold greater than previous high concentration report) using recently developed triblock copolymers and copolymeric nanolatexes based on a reactive ionic liquid acrylate surfactant. We demonstrate that the visible absorption coefficient in aqueous dispersion, 48.9 ± 1.

Triblock copolymer based on poly(propylene oxide) and poly(1-[11-acryloylundecyl]-3-methyl-imidazolium bromide).

The controlled atom transfer radical polymerization of an ionic liquid, 1-(11-acryloylundecyl)-3-methyl imidazolium bromide (ILBr), from both ends of a telechelic poly(propylene oxide) (PPO) macroinitiator, end-functionalized with bromoisobutyryloyl is reported. The resulting highly water-soluble triblock, poly(ILBr-b-PO-b-ILBr) is multistimuli responsive. This new class of triblocks exhibits classical surface activity in lowering surface tension at the air-water interface and in modifying wetting in waterborne coatings.

Polymer dewetting via stimuli responsive structural relaxation-contact angle analysis.

Thin films of a stimuli-responsive homopolymer dewet as a stimulus response after anion exchange of the imidazolium's counter anion. Contact angle analysis and interfacial energy considerations indicate dewetting goes counter to increasing spreading coefficient. Intrafilm stress arising from structural relaxation drives the dewetting.

Stimuli responsive poly(1-[11-acryloylundecyl]-3-methyl-imidazolium bromide): dewetting and nanoparticle condensation phenomena.

A stimuli-responsive homopolymer poly(ILBr) is fabricated via a "two-phase" atom transfer radical polymerization (ATRP) process, where ILBr stands for the reactive ionic liquid surfactant, 1-[11-acryloylundecyl]-3-methyl-imidazolium bromide. An extraordinarily wide molecular weight distribution (PDI = 6.0) was obtained by introducing the initiator (4-bromomethyl methyl benzoate) in a heterogeneous two-phase process.

Fabrication of microneedles using two photon polymerization for transdermal delivery of nanomaterials.

Microneedle devices for transdermal delivery of nanoscale pharmacologic agents were fabricated out of organically-modified ceramic (Ormocer) materials using two photon polymerization. Out-of-plane hollow microneedle arrays with various aspect ratios were fabricated using this rapid prototyping process. Human epidermal keratinocyte (HEK) viability on Ormocer surfaces fabricated using two photon polymerization was similar to that on control surfaces.