Synthesis and Structural Insight into poly(dimethylsiloxane)--poly(2-vinylpyridine) Copolymers.

In this study, the use of anionic polymerization for the synthesis of living poly(dimethylsiloxane) or PDMS-Li, as well as poly(2-vinylpyridine) or P2VP-Li homopolymers, and the subsequent use of chlorosilane chemistry in order for the two blocks to be covalently joined leading to PDMS--P2VP copolymers is proposed. High vacuum manipulations enabled the synthesis of well-defined materials with different molecular weights (Μ¯n, from 9.8 to 36.

Mechanics of an Asymmetric Hard-Soft Lamellar Nanomaterial.

Nanolayered lamellae are common structures in nanoscience and nanotechnology, but most are nearly symmetric in layer thickness. Here, we report on the structure and mechanics of highly asymmetric and thermodynamically stable soft-hard lamellar structures self-assembled from optimally designed PS1-(PI-b-PS2)3 miktoarm star block copolymers. The remarkable mechanical properties of these strong and ductile PS (polystyrene)-based nanomaterials can be tuned over a broad range by varying the hard layer thickness while maintaining the soft layer thickness constant at 13 nm.

Fabrication of ultra-dense sub-10 nm in-plane Si nanowire arrays by using a novel block copolymer method: optical properties.

The use of a low-χ, symmetric block copolymer as an alternative to the high-χ systems currently being translated towards industrial silicon chip manufacture has been demonstrated. Here, the methodology for generating on-chip, etch resistant masks and subsequent pattern transfer to the substrate using ultra-small dimension, lamellar, microphase separated polystyrene-b-poly(ethylene oxide) (PS-b-PEO) block copolymer (BCP) is described. Well-controlled films of a perpendicularly oriented lamellar pattern with a domain size of ∼8 nm were achieved through amplification of an effective interaction parameter (χeff) of the BCP system.

Creating Extremely Asymmetric Lamellar Structures via Fluctuation-Assisted Unbinding of Miktoarm Star Block Copolymer Alloys.

We report the creation of highly asymmetric lamellar structures with a well-designed miktoarm star block copolymer of the S(IS')3 type, where S and S' are polystyrenes of different lengths and I is poly(isoprene). The domain spacing can be tuned continuously from 37 nm to over 300 nm when the miktoarm star block copolymer is blended with suitable molecular weight polystyrene homopolymers. Beyond the unbinding transition of the lamellar phase, extremely asymmetric lamellar structures were obtained with up to 97 wt % polystyrene, remarkably leaving the poly(isoprene) layers intact at only 3 wt %!