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To control the self-assembled morphology of block copolymers (BCPs), a series of BCPs were synthesized and post-functionalized via click chemistry. More specifically, polystyrene-b-poly(allyl glycidyl ether)s (PS-b-PAGEs) were synthesized via the anionic polymerization of styrene and subsequent catalyzed ring-opening polymerization of the second PAGE block. Thiol窶兎ne click chemistry was utilized for the post-functionalization of the resulting polymers. To investigate the effects of functional side-chains on the interaction between segments, the Flory窶滴uggins interaction parameter ﾏ� was estimated using the radon phase approximation method. The significant increases and decreases in the effective ﾏ� (ﾏ㌃ff) values obtained suggested that the introduction of functional groups significantly influenced ﾏ㌃ff. Moreover, the morphologies of the synthesized BCPs were then investigated using X-ray scattering and transmission electron microscopy, and it was found that the morphology was also affected by the introduction of functional groups.

A facile approach to block copolymer (BCP) domain orientation control in thin films has been demonstrated by employing a BCP with liquid crystalline semifluorinated side chains by tuning the composition of the copolymers of the bottom surface layer (BSL). 1H,1H,2H,2H-Perfluorodecanethiol was attached to a precursor polymer, polystyrene-block-poly(glycidyl methacrylate) (PS-b-PGMA), to obtain a novel BCP with a C8F17-containing liquid crystal (LC) side chain (PS-b-P8FMA). Anisotropic hexagonally packed cylinder domains in a bulk state were first characterized by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The observed morphology transition of BCPs with different fluorinated side chain lengths of –CF3, –C4F9, and –C6F13 suggested the decisive effects of LC side chain ordering on the anisotropic nanostructures. In the thin film study, poly(methyl methacrylate-random-2,2,2-trifluoroethyl methacrylate-random-methacrylic acid) (PMMA-ran-PTFEMA-ran-PMAA) solution was used as BSLs for tuning the desired periodicities. The surface free energy (SFE) of BSL was simply tailored by changing the composition of comonomers. In atomic force microscopy (AFM) characterization, long-range ordered perpendicularly oriented BCP domains in a hexagonally packed array or parallel oriented BCP domains as striation patterns were easily fabricated on non-preferential or preferential BSL, respectively. The study presents a novel approach to tunable thin film periodicities without changing or modifying BCPs, which is desired in next-generation BCP lithography.

A precursor diblock copolymer with a silicon backbone, polystyrene-block-poly(methylvinylsiloxane), was synthesized, and 1H,1H,2H,2H-perfluorodecanethiol was quantitatively introduced into the backbone via a thiol-ene reaction to yield a novel coil窶途od diblock copolymer, poly(styrene-block-poly(2-((3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)thio)ethyl)methylsiloxane). The ultra-hydrophobicity of the introduced perfluoroalkyl side chain enhanced the segregation between counter-blocks and significantly increased the ﾏ� value, which is essential for minimizing the size of self-assembled domains for lithographic applications. Thus, self-assembled domains with a minimal spacing of approximately 10 nm were formed. A hexagonally packed array with significant anisotropy was observed in the self-assembled morphology by small-angle X-ray scattering and transmission electron microscopy. Such an array was precisely reproduced by modified self-consistent field theory (SCFT) calculation developed for the coil窶途od structure. Furthermore, the phase diagram was estimated, and the morphological dependence on the relative scale of the rod unit was investigated by SCFT prediction.

Using a tailorable poly(styrene-block-glycidyl methacrylate-block-methyl methacrylate) (PS-b-PGMA-b-PMMA) triblock terpolymer, the effect of changing the Flory窶滴uggins interaction parameters (ﾏ�) on the bulk self-assembly behavior of 12 linear ABC triblock terpolymers was investigated. By introducing different thiols to the short, reactive PGMA middle block, the experimental ﾏ②B and ﾏ③C could be arbitrarily altered, thereby changing the self-assembled morphologies that were characterized by small-angle X-ray scattering and transmission electron microscopy. Observed morphologies included lamellae, hexagonal cylinders, and tetragonal cylinders, which were found to be in close agreement with the expected morphologies obtained by self-consistent field theory simulation. Extending the 12 experimental results, 400 simulations were carried out to construct the ﾏ②B窶苫③C phase diagrams of the terpolymer at four different degrees of polymerization. The experimental and simulation results demonstrated that both the magnitude and the relation among each of the three interaction parameters are vital in determining the self-assembled morphology.