Nanoordering of Fluorinated Side-Chain Liquid Crystalline/Amorphous Diblock Copolymers

Abstract

The role of anchoring the mesogenic side chains at the internal and boundary interfaces in the thin film morphology has been investigated for two fluorinated side-chain liquid crystalline/amorphous diblock copolymers. Initial bulk investigations indicate that the two polymers strongly microphase segregate into a cylindrical and a lamellar morphology, respectively. Inside the liquid-crystal block, the cylinder-forming block copolymer shows both a crystalline-B and a smectic-A phase, whereas the lamellaeforming polymer gives only a smectic-A phase, with the side chains organized in double layers with a spacing of 3.33 nm. In both situations the smectic layers are oriented perpendicular to the block interfaces, which state is retained in films. In thin films of the cylinder-forming block copolymer, the smectic layering and the orientational wetting properties of the fluorinated side chains stabilize the minority cylindrical domains normal to the substrate. For films of the lamellar system, however, an evolved structure forms with block lamellae parallel to the substrate in combination with anchoring of the fluorinated chains at the surface of the film.

Thin Film Morphologies of Block Copolymers Complexed with Wedge-Shaped Liquid Crystalline Amphiphilic Molecules

“…This is in agreement with other thin film studies of smectic/amorphous BC's. 18,19 Evidently the formation of liquid crystalline layers parallel to the interfaces is the major driving force determining the final morphology. It is remarkable that, independently of composition, the PEO microdomains of the P2VP 180 -b-PEO 560 (1-H) x samples with x ) 0.25 and 0.5 adopt a vertical orientation with respect to the surface and thus parallel to the LC field of the mesogens.…”

Semifluorinated Methacrylate Random Copolymers: Phase Transitions and Molecular Dynamics

“…Comparable values were found for the copolymers with 11 and 31 mol% of sfMA, while for the sample with 68 mol% the relaxation becomes double. The copolymers where the side chains are organized follow the additive rule, however the values in these samples are lower than those expected taking into account the value observed for the 11 of dielectric strength due to cancellation of dipole moments. A relaxation with similar characteristics has already been observed in systems having fluoroalkanes as side chains and has been ascribed to motions of CF 3 -groups [19,20,22,29].…”

“…A strong tendency to form a smectic phase has been reported for these systems [1][2][3][4]. The tendency of sf segments to get organized in smectic structures have been found to persist when sf chains are attached in polymer backbone as side chains either in form of a sf homopolymer or a sf copolymer [5][6][7][8][9][10][11]. The effects of the formation of an ordered structure on the surface of sf polymer thin films on the surface properties such as surface energy and stability have been reported [5][6][7][8][12][13][14].…”

The Distribution of Immobilized Platinum and Palladium Nanoparticles within Poly(2‐vinylpyridine) Brushes

“…[ 27,28 ] X-ray specular refl ectivity provides information on the average electron density normal to the surface and can be used to determine the concentration of atomic species at a particular depth in thin polymer fi lms. [29][30][31] Using this approach, we followed the formation steps of the polymer brush and extracted information about the brush layers. Then, we quantifi ed the electron density distributions of immobilized Pt and Pd NPs in P2VP polymer brushes.…”