In this study, a series of perpendicular lamellae-forming poly(polyhedral oligomeric silsesquioxane methacrylate-block-2,2,2-trifluoroethyl methacrylate)s (PMAPOSS-b-PTFEMAs) was developed based on the bottom-up concept of creating a simple yet effective material by tailoring the chemical properties and molecular composition of the material. The use of silicon (Si)-containing hybrid high-χ block copolymers (BCPs) provides easy access to sub-10 nm feature sizes. However, as the surface free energies (SFEs) of Si-containing polymers are typically vastly lower than organic polymers, this tends to result in the selective segregation of the inorganic block onto the air interface and increased difficulty in controlling the BCP orientation in thin films. Therefore, by balancing the SFEs between the organic and inorganic blocks through the use of poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) on the organic block, a polymer with an SFE similar to Si-containing polymers, orientation control of the BCP domains in thin films becomes much simpler. Herein, perpendicularly oriented BCP thin films with a χ value of 0.45 were fabricated using simple spin-coating and thermal annealing processes under ambient conditions. The thin films displayed a minimum domain size of L = 11 nm, as observed via atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Furthermore, directed self-assembly (DSA) of the BCP on a topographically prepatterned substrate using the grapho-epitaxy method was used to successfully obtain perpendicularly oriented lamellae with a half pitch size of ca. 8 nm.

An instrumentation technique for real-time, in situ and real space observation of microphase separation was proposed for ultra-high molecular weight block copolymer thin films (1010 kg mol À1 , domain spacing of 180 nm) under high solvent vapor swelling conditions. This is made possible by a combination of a homebuilt chamber which is capable of supplying sufficient amount of vapor, and force-distance curve measurements which gives real-time swollen film thickness and allow active feedback for controlling the degree of swelling. We succeeded in monitoring the domain coarsening of perpendicular lamellar structures in polystyrene-block-poly(methyl methacrylate) thin films for eight hours via tapping mode imaging. During the annealing process, the thickness reached a maximum of 8.5 times that of the original film. The series of temporal real space topographic images obtained via this method allowed us to study, for the first time, the growth exponent of the correlation length under solvent vapor annealing. † Electronic supplementary information (ESI) available: Solvent vapor annealing using reectometry, selective swelling of PS and PMMA homopolymers in THF, USAXS measurement of bulk BCP phase-separated pellets, defect analysis of AFM topographic images, and morphology assignment by SEM. See

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feature sizes and high aspect ratios for pattern transfer can be obtained. [6][7][8] Typically, such BCP thin films are prepared by spin-coating a dilute BCP solution onto silicon (Si) substrates. However, these as-cast BCP thin films exhibit a locally segregated, disordered morphology. [9][10][11] Although perpendicular lamellar structures can be obtained by various annealing processes, high defectivity in the resultant thin films reduces the potential for industrial applications. Furthermore, although chemical and physical guides can be used to alleviate the thin film defectivity, [6,[12][13][14][15] BCP thin films that can meet the industrial requirements of 0.01 defects cm −2 have yet to be developed.The difficulty in obtaining defect-free BCP thin films can be attributed to a lack of understanding and experimental documentation in the early-stage evolution of ordered structures and defects in perpendicular lamellar thin films. Previous studies on the evolution of ordered structures in thin films have focused on the formation of parallel lamellae with island-hole structures, [16][17][18] and late-stage defect dynamics, [9,[19][20][21][22][23][24][25][26] particularly using low-χ or parallel cylinder-forming BCPs. Capturing the real time evolution of perpendicular lamellae in situ has been difficult as BCP selfassembly tends to occur in shorter time frames than most characterization equipment can analyze the thin films and the fact that parallel structures tend to form due to interfacial selectivity at the substrate and free surfaces. However, by utilizing newer technology such as high-speed atomic force microscopy (AFM) equipped with a heating unit for in situ characterization of the annealing process in a wide temperature window from room temperature to above the glass transition temperature (T g ) of the BCP, the self-assembly behavior of BCP thin films can be documented in real time and space. Additionally, although differences in the surface free energies (SFEs) between the BCP components tend to induce the preferential interfacial segregation of one block, by balancing the surface affinities of both blocks or introducing chemically modifying layers to tune the chemical affinities of the interfaces, the selective segregation of one block can be prevented, The evolution of well-ordered, sub-10 nm, perpendicular lamellae from a disordered state is documented directly using in situ atomic force microscopy, cross-sectional scanning electron microscopy, and grazing-incidence small angle X-ray scattering. Since block copolymer (BCP) self-assembly occurs on extremely fast time scales, directly imaging the growth of perpendicular lamellae remains challenging. The lack of understanding behind early-stage self-assembly and how metastable defects can affect the kinetic behavior near thermodynamic equilibrium prevents the realization of defect-free thin films. By characterizing the evolution of nanostructures using a high-χ, perpendicular lamella-forming BCP, poly(polyhedral oligomeric silsesquioxane)-blockpoly(2,2,2...