Discussion on "Aperiodic Copolymers".

In a recent Viewpoint ( , , 1020), J.-F. Lutz brought to the community's attention the need for more informative nomenclature, especially with respect to macromolecules with prescribed but not repeating sequences of monomers.

A Novel Method of Extraction of Blend Component Structure from SANS Measurements of Homopolymer Bimodal Blends.

A new method is presented for the extraction of single-chain form factors and interchain interference functions from a range of small-angle neutron scattering (SANS) experiments on bimodal homopolymer blends. The method requires a minimum of three blends, made up of hydrogenated and deuterated components with matched degree of polymerization at two different chain lengths, but with carefully varying deuteration levels. The method is validated through an experimental study on polystyrene homopolymer bimodal blends with [Formula: see text].

In Silico Molecular Design, Synthesis, Characterization, and Rheology of Dendritically Branched Polymers: Closing the Design Loop.

It has been a long held ambition of both industry and academia to understand the relationship between the often complex molecular architecture of polymer chains and their melt flow properties, with the goal of building robust theoretical models to predict their rheology. The established key to this is the use of well-defined, model polymers, homogeneous in chain length and architecture. We describe here for the first time, the in silico design, synthesis, and characterization of an architecturally complex, branched polymer with the optimal rheological properties for such structure-property correlation studies.

Surface modification of polyethylene with multi-end-functional polyethylene additives.

We have prepared and characterized a series of multifluorocarbon end-functional polyethylene additives, which when blended with polyethylene matrices increase surface hydrophobicity and lipophobicity. Water contact angles of >112° were observed on spin-cast blended film surfaces containing less than 1% fluorocarbon in the bulk, compared to ~98° in the absence of any additive. Crystallinity in these films gives rise to surface roughness that is an order of magnitude greater than is typical for amorphous spin-cast films but is too little to give rise to superhydrophobicity.

Kinetic control of monomer sequence distribution in living anionic copolymerisation.

Sequence control in synthetic polymers is a subject that is sparsely reported with little research in the field of sequence control in chain growth polymerisation. We report herein preliminary investigations into anionic copolymerisation of diphenylethylene (DPE) and its derivatives with styrene. DPE is a monomer that will only copolymerise and can form alternating copolymers.

Nonsolvent annealing polymer films with ionic liquids.

Neutron reflectometry has been used to determine the interface structure and swelling of thin polymer films, when annealed in contact with a series of 1-alkyl-3-methylimidazolium ionic liquids (ILs). By choosing immiscible polymer/IL combinations, we have established that thin polymer films can be annealed for several hours in contact with ILs at temperatures well above the glass transition temperature and that this nonsolvent annealing environment can be exploited to direct self-assembly in polymer films. The ingress of IL into polymer films was quantified in terms of the swelling up to 10%.

pH-controlled polymer surface segregation.

A new approach to promoting and controlling polymer surface functionalization with acidic or basic polar functional groups is demonstrated and evaluated. Blended polymer films were annealed under pH-buffered conditions, and polar end-functional groups were found to promote surface segregation of the functional polymers. Surface segregation of carboxylic acid (COOH)-functionalized polystyrene increases dramatically with increasing pH from 1.

Aggregation, adsorption, and surface properties of multiply end-functionalized polystyrenes.

The properties of polystyrene blends containing deuteriopolystyrene, multiply end-functionalized with C8F17 fluorocarbon groups, are strikingly analogous to those of surfactants in solution. These materials, denoted FxdPSy, where x is the number of fluorocarbon groups and y is the molecular weight of the dPS chain in kg/mol, were blended with unfunctionalized polystyrene, hPS. Nuclear reaction analysis experiments show that FxdPSy polymers adsorb spontaneously to solution and blend surfaces, resulting in a reduction in surface energy inferred from contact angle analysis.

Surface adsorption of polar end-functionalised polystyrenes.

Due to their inherently high surface energy, polar end-functionalised polymers do not normally adsorb to the external surfaces of blends. However, adsorption of polar functionalities can be induced rapidly by annealing in a polar environment such as glycerol prior to quenching to a glassy state. Blended films of carboxy end-functionalised deuteriopolystyrene (dPS-COOH) with hydrogenous polystyrene (hPS) were annealed at 150 °C under glycerol.

Novel multi end-functionalised polymers. Additives to modify polymer properties at surfaces and interfaces.

Fréchet-type poly(arylether) dendrons with up to eight trifluoromethyl peripheral groups have been used as initiators in the copper mediated living radical polymerisation of d-styrene, the surface adsorption behaviour and resulting properties of these polymers in blends have been investigated by ion beam analysis and contact angle measurements.