Application of Solvent-Directed Assembly of Block Copolymers to the Synthesis of Nanostructured Materials with Low Dielectric Constants

Strategies for the synthesis of block copolymers with biodegradable polyester segments

Oxygenated block copolymers with biodegradable polyester segments can be prepared in one-pot through sequential or simultaneous addition of monomers. This review highlights the state of the art in this area.

Robust spin-on-glass poly(methyl)silsesquioxane-based low-k materials derived from a cyclic siloxane precursor

Low dielectric constant poly(methyl)silsesquioxane spin-on-glass resins incorporating a cyclic precursor exhibited exceptional mechanical properties to withstand CMP processes.

Three-dimensional nanofabrication by block copolymer self-assembly

Thin films of block copolymers are widely seen as enablers for nanoscale fabrication of semiconductor devices, membranes, and other structures, taking advantage of microphase separation to produce well-organized nanostructures with periods of a few nm and above. However, the inherently three-dimensional structure of block copolymer microdomains could enable them to make 3D devices and structures directly, which could lead to efficient fabrication of complex heterogeneous structures. This article reviews recent progress in developing 3D nanofabrication processes based on block copolymers.

Nanofabrication at high throughput and low cost

The task of nanofabrication can, in principle, be divided into two separate tracks: generation and replication of the patterned features. These two tracks are different in terms of characteristics, requirements, and aspects of emphasis. In general, generation of patterns is commonly achieved in a serial fashion using techniques that are typically slow, making this process only practical for making a small number of copies. Only when combined with a rapid duplication technique will fabrication at high-throughput and low-cost become feasible. Nanoskiving is unique in that it can be used for both generation and duplication of patterned nanostructures.

Hierarchical assembly of nanostructured organosilicate networks via stereocomplexation of block copolymers

The effect of the stereochemistry of polylactide (PLA)-based block copolymers on templated inorganic nanostructures has been investigated from the self-assembly of a stereoisomer pair/organosilicate mixture followed by organosilicate vitrification and copolymer thermolysis. Isomeric PLA homopolymers, block copolymers, and a stereoblock copolymer were prepared by ring-opening polymerization of D-, L-, or rac-lactide using an organocatalytic catalyst. Both differential scanning calorimetry and atomic force microscopy showed the formation of a stereocomplex between enantiomeric stereoisomers, that is, block copolymer/block copolymer and block copolymer/homopolymer mixtures as well as a stereoblock copolymer. The unique noncovalent interactions driven by stereocomplexation of D- and L-lactide provided supramolecular structures with a hierarchical order as characterized by distinctive vertical and horizontal growth of toroidal nanostructured inorganic features. This study demonstrates the potential of hierarchically assembling suprastructures that bridge the nano- to mesoscale feature sizes in the design of tunable functional nanomaterials suitable for future applications of microelectronics, material science, and bioengineering.