Conformation of Single Homopolymer Chain in Microphase-Separated Block Copolymer Monolayer Studied by Scanning Near-Field Optical Microscopy

Abstract

The phase-separated structure of poly(isobutyl methacrylate)-block-poly(octadecyl methacrylate) (PiBMA-b-PODMA) monolayer and single poly(isobutyl methacrylate) (PiBMA) chain dispersed therein were investigated by scanning near-field optical microscopy (SNOM), which enabled us to observe with high spatial resolution beyond the diffraction limit of light. The conformation of the individual homo-PiBMA chains was quantitatively evaluated from the fluorescence intensity distribution. We found that the homo-PiBMA chains were almost located at the center of the PiBMA domain. The homo-PiBMA chain was oriented itself depending on its location in the PiBMA domain. When the homo-PiBMA chain locates at the center of the PiBMA domain, it tends to orient itself in the direction parallel to the interface between the two microdomains. When the homo-PiBMA chain locates near the interface, it orients itself in the direction perpendicular to the interface.

Symmetry breaking in particle-forming diblock polymer/homopolymer blends

“…An outstanding question related to the volume-asymmetry mechanism is whether the selective partitioning of the homopolymers to the larger particles can be observed experimentally. There is a body of prior work on combining small-angle X-ray scattering and small-angle neutron scattering to identify the locations of homopolymers in block-polymer microstructures (42,43), and microscopy has also been employed for this purpose (44). The small domain sizes of the particles in these phases and the subtle (but important) differences in A-polymer volume fractions within different particles pose nontrivial experimental obstacles, but it may be possible to observe the partitioning effect through changes in the relative intensity of the scattering from the Z16 particles in C15 relative to the Z12 particles as the homopolymer volume fraction increases.…”

Scanning Force Microscopy as Applied to Conformational Studies in Macromolecular Research

“…SNOM was successfully applied to study conformations of single dye-labelled poly(isobutylmethacrylate) chains in dense films. [327][328][329] For homogeneous LB monolayers strong segregation of polymer chains was detected with the value of n $ 1=2. [327] SFM was applied to study the conformation of individual comb-like macromolecules surrounded by a dense Langmuir monolayer with the polymer chains of the same nature as the side chains.…”

Transmission Electron Microtomography and Polymer Nanostructures

“…Because the packing frustration arises from deviation in the chains from their preferred conformation, scientists plan to devise methods to visualize the chain conformation not only in bulk [116][117][118][119][120][121] but also in restricted dimensions. [122][123][124] Small-angle neutron (or X-ray) scattering has been used to evaluate the gyration radius R g of the subchains in lamellar-forming block copolymers. [116][117][118][119] The results of these evaluations have shown that the lateral interpenetration of the subchains is smaller than the interpenetration normal to the interface.…”