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Log-Rolling Block Copolymer Cylinders
Kim, Ye Chan,Kim, Dong Hyup,Joo, Se Hun,Kwon, Na Kyung,Shin, Tae Joo,Register, Richard A.,Kwak, Sang Kyu,Kim, So Youn American Chemical Society 2017 Macromolecules Vol.50 No.9
<P>Shear is an effective method to create long-range order in micro- or nanostructured soft materials. When simple shear flow is applied, particles or polymer microdomains tend to align in the shear direction to minimize viscous dissipation; thus, transverse alignment (so-called log-rolling) is not typically favored. This is the first study to report the transverse alignment of cylinder-forming coil coil block copolymers. Poly(styrene-b-methyl methacrylate), PS PMMA, where the PS blocks form the matrix, can adopt a metastable PMMA hemicylindrical structure when confined in a thin film, and this hemicylindrical structure can orient either along the shear direction or transverse to the shear direction depending on the shearing temperature. A monolayer of PS PMMA forming full cylinders exhibits log-rolling alignment. This unusual log-rolling behavior is explained by the low chain mobility of the cylinder-forming PMMA block at low temperatures, which is direction of shear alignment. the critical quantity determining the</P>
Large-Area Nanosquare Arrays from Shear-Aligned Block Copolymer Thin Films
Kim, So Youn,Nunns, Adam,Gwyther, Jessica,Davis, Raleigh L.,Manners, Ian,Chaikin, Paul M.,Register, Richard A. American Chemical Society 2014 NANO LETTERS Vol.14 No.10
<P>While block copolymer lithography has been broadly applied as a bottom-up patterning technique, only a few nanopattern symmetries, such as hexagonally packed dots or parallel stripes, can be produced by spontaneous self-assembly of simple diblock copolymers; even a simple square packing has heretofore required more intricate macromolecular architectures or nanoscale substrate prepatterning. In this study, we demonstrate that square, rectangular, and rhombic arrays can be created via shear-alignment of distinct layers of cylinder-forming block copolymers, coupled with cross-linking of the layers using ultraviolet light. Furthermore, these block copolymer arrays can in turn be used as templates to fabricate dense, substrate-supported arrays of nanostructures comprising a wide variety of elements: deep (>50 nm) nanowells, nanoposts, and thin metal nanodots (3 nm thick, 35 nm pitch) are all demonstrated.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-10/nl502416b/production/images/medium/nl-2014-02416b_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl502416b'>ACS Electronic Supporting Info</A></P>
Freedman, Barry I,Bowden, Donald W,Ziegler, Julie T,Langefeld, Carl D,Lehtinen, Allison B,Rudock, Megan E,Lenchik, Leon,Hruska, Keith A,Register, Thomas C,Carr, J Jeffrey Mary Ann Liebert, Inc 2009 Journal of bone and mineral research Vol.24 No.10
<P>Inverse relationships have been observed between BMD and vascular calcification (VC), suggesting an underlying metabolic pathway linking these processes. Bone morphogenetic proteins (BMPs) are potential candidate genes that may mediate this relationship. Four single nucleotide polymorphisms (SNPs) in the BMP2 gene, 2 SNPs in BMP4, and 16 SNPs in BMP7 were tested for association with measures of VC using CT (coronary and carotid arteries, abdominal aorta), and BMD was measured using DXA (lumbar spine, hip, and distal radius) and quantitative CT (QCT; thoracic and lumbar spine) in 920 European Americans from 374 Diabetes Heart Study families: 762 with type 2 diabetes. Variance components quantitative trait locus association analysis was computed using SOLAR software, and a bivariate principal component analysis (PCA) assessed for genetic relationships between BMD and VC. Association was observed between several measures of BMD and BMP7 rs17404303 (thoracic spine QCT p = 0.03; lumbar spine QCT p = 0.02; hip DXA p = 0.06, dominant models). In addition, 6 of 16 BMP7 SNPs showed significant and opposing effects on the bivariate PCA for VC and BMD (two-sided exact test, p = 0.0143). Polymorphisms in BMP7 are associated with inverse relationships between bone mineralization and VC in the coronary, carotid, and abdominal aorta in a diabetes-enriched cohort of European Americans.</P>