Morphology of Ultrathin Supported Diblock Copolymer Films:  Theory and Experiment

Abstract

An analysis of the morphological behavior of substrate-supported diblock copolymer films for thicknesses t below the equilibrium period L 0 of the copolymer is presented. Substrate-supported films generally exhibit dissimilar interactions between the copolymer block components and the free and substrate surfaces. Accordingly, in this study, self-consistent-field calculations that incorporate asymmetric surface energetics were used to assess equilibrium film morphologies. Phase diagrams were constructed as a function of film thickness, surface interaction energies, the segmental interaction, and the chain length. In conjunction, experiments were conducted on a series of polystyrene-b-poly(n-alkyl methacrylate) copolymer films supported by silicon substrates. These employed a novel atomic force microscopy technique that allowed for the precise tracking of morphology as a function of film thickness. Comparison of the experimental results and calculations revealed several common trends. In particular, hybrid morphologies, incorporating both surface-parallel and surface-perpendicular elements, were observed both experimentally and through the calculations for the thickness regime, t ∼ 0.5L 0. The stability of such structures was found to be closely linked to the symmetry of the surface energetics.

Protein Nanopatterning on Self-Organized Poly(styrene-b-isoprene) Thin Film Templates

“…At a thickness of 19 nm, almost all of the PI surface domains form uniform dots surrounded by the PS matrix (Fig 1c). Drawing on the structures reported for PS-b-PLMA films, which was called a hybrid structure, 39 we propose that the PS surface shown here in The PI component has a strong interaction with the Si substrate and a lower surface free energy compared with the PS component. 29 Therefore, we expect that in thicker films the PI will wet the Si substrate and also create a wetting layer at the free surface to minimize the total interfacial free energy when in an equilibrium state.…”

Creation of Functional and Structured Polymer Particles by Self-Organized Precipitation (SORP)

“…46 The confinement effect on block copolymers is a significant topic in the nanoscale characterization of polymer materials. One-dimensional (in thin films) 47 or two-dimensional (in porous materials) 48 confinement effects on microphaseseparated structures of block copolymers have been extensively studied both theoretically and experimentally, however there are few experimental studies of three-dimensional confinement systems. Ozin and Manners showed that lamellar layers of poly(styrene-block-ferrocenylethylmethylsilane) align along the spherically confined spaces in the inverse opal templates of silica.…”

Spreading of block copolymer films and domain alignment at moving terrace steps

“…Similarly, in the macroscopic drop region, domain orientation may be expected to be random and macroscopic viscosity remains isotropic. Hence, the domain structure may be accounted for via a macroscopic viscosity so that general spreading dynamics still follows the Tanner's law (4).…”

“…Equilibrium structure of block copolymer systems was in the center of theoretical and experimental research for a number of years now, and is mostly understood 2,3,4,5,6,7,8,9 . It is known that in the bulk, at temperatures below order-disorder transition (ODT), molten diblock copolymers phase-separate into periodic structures with periodicity dependent on polymer size.…”