Cross-domain Chirality Transfer in Self-Assembly of Chiral Block Copolymers.

Chirality transfer is essential to acquire helical hierarchical superstructures from the self-assembly of supramolecular materials. By taking advantage of chirality transfers at different length scales through intra-chain and inter-chain chiral interactions, helical phase (H*) can be formed from the self-assembly of chiral block copolymers (BCPs*). In this study, chiral triblock terpolymers, polystyrene-b-poly(ethylene oxide)-b-poly(L-lactide) (PS-PEO-PLLA), and polystyrene-b-poly(4-vinylpyridine)-b-poly(L-lactide) (PS-P4VP-PLLA) are synthesized for self-assembly.

Starfish-Inspired Diamond-Structured Calcite Single Crystals from a Bottom-up Approach as Mechanical Metamaterials.

Inspired by knobby starfish, this work demonstrates a bottom-up approach for fabricating a calcite single-crystal (CSC) with a diamond structure by exploiting the self-assembly of the block copolymer and corresponding templated synthesis. Similar to the knobby starfish, the diamond structure of the CSC gives rise to a brittle-to-ductile transition. Most interestingly, the diamond-structured CSC fabricated exhibits exceptional specific energy absorption and strength with lightweight character superior to natural materials and artificial counterparts from a top-down approach due to the nanosized effect.

Well-Ordered Nanonetwork Metamaterials from Block Copolymer Templated Syntheses.

Through the morphological evolution to give highly optimized complex architectures at different length scales, fine-tuned textures for specific functions in living organisms can be achieved in nature such as a bone core with very complicated porous architecture to attain a significant structural efficiency attributed to delicately structured ligaments and density gradients. As inspired by nature, materials with periodic network structures (i.e.

Mesoscale networks and corresponding transitions from self-assembly of block copolymers.

A series of cubic network phases was obtained from the self-assembly of a single-composition lamellae (L)-forming block copolymer (BCP) polystyrene-block-polydimethylsiloxane (PS--PDMS) through solution casting using a PS-selective solvent. An unusual network phase in diblock copolymers, double-primitive phase (DP) with space group of [Formula: see text], can be observed. With the reduction of solvent evaporation rate for solution casting, a double-diamond phase (DD) with space group of [Formula: see text] can be formed.

Networks with controlled chirality via self-assembly of chiral triblock terpolymers.

Nanonetwork-structured materials can be found in nature and synthetic materials. A double gyroid (DG) with a pair of chiral networks but opposite chirality can be formed from the self-assembly of diblock copolymers. For triblock terpolymers, an alternating gyroid (G) with two chiral networks from distinct end blocks can be formed; however, the network chirality could be positive or negative arbitrarily, giving an achiral phase.

Examination of well ordered nanonetwork materials by real- and reciprocal-space imaging.

The development of well ordered nanonetwork materials (in particular gyroid-structured materials) has been investigated using a block-copolymer template for templated electroless plating as an example system for the examination of network formation using X-ray scattering. By taking advantage of the nucleation and growth mechanism of templated electroless plating, gyroid-structured Au was successfully fabricated through the development of Au nanoparticles, then tripods and branched tripods, and finally an ordered network. Each stage in the development of the network phase could then be examined by combining real-space transmission electron microscopy observations with reciprocal-space small-angle X-ray scattering results.