Pyramid Spectral Analysis of Narrow-Band Signal

Effect of Chain Persistence Length on the Moduli of Block Copolymer Films

“…This will translate to an increase in the bending modulus (resistance to bending) and a decrease in the Gaussian modulus (resistance to saddle splay). This is consistent with the analogy between chains, the chain persistence length, and changing the chain asymmetry or the ratio of the two block molecular weights . However, contrary to this expectation, we find that increasing the chain stiffness leads to a maximum in the bending modulus; beyond a critical value, the layer resistance to bending decreases with chain stiffness to values below those of the fully flexible diblock.…”

“…Diblock copolymers, the macromolecular analogue of small molecule surfactants, are similarly used to stabilize incompatible polymer blends. Understanding the relationship between copolymer properties and the self-assembled interfacial layer characteristics is important, since these control the type, size, and polydispersity of the stable domains. − …”

“…Interfacial layers of flexible diblock copolymers (where the persistence lengths of both blocks are of the same order as the monomer size) at the interface between immiscible liquids 1,2 or homopolymers 3-6 have been thoroughly examined. The layer characteristics are controlled by a balance between the entropy of the two blocks and the strength of the interactions between them. − …”

Influence of Segmental Swelling Ratio of a Symmetric Block Copolymer on the Morphology of Melt-Mixed Immiscible Polymer Blends

“…In the PCHMA/SAN33/bcp system, which has a swelling ratio of S out / S in = 4.3, droplet coalescence is also observed, and the morphology shows very small micelles in the matrix coexisting with larger coalesced droplets (Figure a,b). This discrete bimodal size distribution is characteristic of emulsification failure, which has been described theoretically , and experimentally in solvent-cast blend systems. Emulsification failure occurs when the interfacial tension is finite at the point that the interface is saturated with copolymer, and excess copolymer exists in micelles within the phase in which it is more soluble. , (Note that micelles may be swollen with homopolymer.)…”

“…This discrete bimodal size distribution is characteristic of emulsification failure, which has been described theoretically , and experimentally in solvent-cast blend systems. Emulsification failure occurs when the interfacial tension is finite at the point that the interface is saturated with copolymer, and excess copolymer exists in micelles within the phase in which it is more soluble. , (Note that micelles may be swollen with homopolymer.) The term failure is used, because only some of the copolymer is at the macrophase interface, and the rest of the copolymer is ineffective in reducing the droplet size.…”