Kim, Seyoung Yoo, Misang Baettig, Julia Kang, Eun-Hye Koo, Jaseung Choe, Youngson Choi, Tae-Lim Khan, Anzar Son, Jeong Gon Bang, Joona 2024-01-20T08:02:53Z 2024-01-20T08:02:53Z 2021-09-05 2015-01 2161-1653 https://pubs.kist.re.kr/handle/201004/125943 By introducing neutral star copolymers consisting of poly(styrene-r-methyl methacrylate) (PS-r-PMMA) arms, a perpendicular orientation of PS-b-PMMA microdomains in thin films could be achieved without any surface treatment. The star copolymers were synthesized by arm-first method in which short chain arms are cross-linked by employing a multifunctional coupling reagent via atom transfer radical polymerization. To find the optimal neutral composition for the perpendicular orientation, we varied the composition of MMA in PS-r-PMMA arms from 40 mol % to 80 mol %. It was found that the star copolymer having an overall PS and PMMA composition of 59:41 exhibits the well-ordered perpendicular orientation of lamellar structures after thermal annealing. Furthermore, we also prepared the deuterated star copolymers to trace them within PS-b-PMMA films along vertical direction by neutron reflectivity. In this case, it was observed that star copolymers were mainly located at the top surface and bottom interface of the films, thereby effectively neutralizing the surface/interfacial energy differences. English AMER CHEMICAL SOC TRANSFER RADICAL POLYMERIZATION SURFACE NEUTRALIZATION ORIENTATION MICRODOMAINS LITHOGRAPHY Perpendicularly Oriented Block Copolymer Thin Films Induced by Neutral Star Copolymer Nanoparticles Article 10.1021/mz500761h 1 ACS MACRO LETTERS, v.4, no.1, pp.133 - 137 ACS MACRO LETTERS 4 1 133 137 scie scopus 000348339300028 2-s2.0-84921325021 Polymer Science Polymer Science Article TRANSFER RADICAL POLYMERIZATION SURFACE NEUTRALIZATION ORIENTATION MICRODOMAINS LITHOGRAPHY Block copolymer Patterning