Hierarchical Nanostructures by Sequential Self‐Assembly of Styrene‐Dimethylsiloxane Block Copolymers of Different Periods

Abstract

Poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) block copolymers with a period as low as 13 nm have been self-assembled on a template formed from PS-b-PDMS of a 34–40 nm period, which is itself templated by micron-scale substrate features prepared using conventional lithography. This hierarchical process provides a simple method for directing the self-assembly of sub-10 nm features and registering them on the substrate.

Rectangular Symmetry Morphologies in a Topographically Templated Block Copolymer

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This method has been used to produce large-area defect-free lamellar, cylindrical, or spherical microdomain patterns through chemical [1][2][3][4][5][6] or topographical [7][8][9][10][11][12][13][14][15] templating. However, the formation of complex patterns with multiple morphologies in one BCP film (e.g.…”

Sub-20 nm Microphase-Separated Structures in Hybrid Block Copolymers Consisting of Polycaprolactone and Maltoheptaose

“…Note that no chain scission and/or decomposition of the PCL main chain was observed during the click reaction. 3 . For the synthesis of MH-b-(PCL) 2 and MH-b-(PCL) 3 , we first prepared the linear and three-branched PCLs bearing an azido group on the chain center (N 3 -(PCL) 2 and N 3 -(PCL) 3 , respectively) by the DPP-catalyzed ROP with 3 ) as the initiators (Scheme 2).…”

“…The obtained azido-functionalized branched PCLs were subjected to the click reaction with MH-C CH to give the AB n -type miktoarm star copolymers consisting of PCL and MH, i.e., MH-b-(PCL) 2 and MH-b-(PCL) 3 , where A and B represent the MH and PCL blocks, respectively. It is worth noting that the click reactions of N 3 -(PCL) 2 and N 3 -(PCL) 3 with MH-C CH well proceeded to give the corresponding products in high yields despite the greater steric crowding around the reactive azido group rather than the linear N 3 -PCL.…”

“…For the synthesis of MH-b-(PCL) 2 and MH-b-(PCL) 3 , we first prepared the linear and three-branched PCLs bearing an azido group on the chain center (N 3 -(PCL) 2 and N 3 -(PCL) 3 , respectively) by the DPP-catalyzed ROP with 3 ) as the initiators (Scheme 2). Two different molecular weight series of N 3 -(PCL) 2 (M n values of 5120 and 10010 g mol -1 ) and N 3 -(PCL) 3 (M n values of 5510 and 10330 g mol -1 ) were synthesized by varying the monomer-to-initiator ratio. The chemical structure, including the arm number as well as the chain end structure, of the obtained PCLs were identified by NMR and mass spectral analyses.…”

“…Several BCP systems, such as polystyreneblock-polydimethylsiloxane [3,4], polystyreneblock-poly(2-ethyl-2-oxazoline) [5], polylactideblock-polydimethylsiloxane-block-polylactide [6], poly(trimethylsilylstyrene)-block-polylactide [7], and a poly(methyl methacrylate)-block-polyhedraloligomeric silsesquioxane-containing polymethacrylate [8], have achieved the sub-20 nm microphase separation due to the strong segregation between the two constitutional blocks. However, only a limited number of BCPs capable of producing such small features are currently available.…”