Rod-Coil 블록 공중합체를 RuPhos Pd 촉매를 이용한 Suzuki-Miyaura catalyst-transfer polycondensation (SCTP) 방법을 이용하여 coil-first/grafting from 접근법으로 새로운 합성법을 개발하였다. 처음 atom transfer radical polymerization (ATRP) 방법을 통해 polystyrene (PS)을 중합하였고 azidation, click 반응을 통해 end group modification하여 coil-type macroinitiator PS (P1)을 합성하였다. 그 후 boronate에 N-methyliminodiacetic acid (MIDA) protecting group를 도입한 3-hexylthiophene monomer (M1)를 이용하여 RuPhos Pd-catalyzed SCTP를 실행했다. 그 결과 well-defined polystyrene(PS)-block-poly(3-hexylthiophene) (P3HT)을 뛰어난 control, 높은 수율로 얻는데 성공하였다. 또한 coil-type macroinitiator의 종류를 넓혀 poly(methyl acrylate) (PMA), poly(methylmethacrylate) (PMMA)를 이용하여 같은 방법으로 poly(methyl acrylate)-block- poly(3-hexylthiophene) (P4), poly(methylmethacrylate)-block- poly(3-hexylthiophene) (P6)을 합성하는데 성공하였다. 이 방법을 응용하여 기존 rod first approach에 이어서 coil block을 합성한 뒤 P3HT와 다른 rod block인 poly(3-ethylhexylthiophene) (P3EHT)을 중합하여 기존에 없던 ABC type의 rod-coil-rod triblock copolymer (P10)를 합성하는데 성공하였다. 하지만 반복되는 end group modification으로 인한 end group fidelity의 부정확성 때문에 반응에 참여하지 못하고 남은 first block이 존재하였다. 이를 극복하기 위해 bifunctional initiator를 준비하여 bromide end group을 제거 한 macroinitiator를 통해 보다 효율적인 coil-type macroinitiator (P14) 전략을 제시하였다. 뿐만 아니라 coil block에 유기용매에 대한 용해도가 좋지 않은 전도성 고분자 polythiophene (PT)을 coil block 고분자에 SCTP 방법으로 중합함으로써 in situ nanoparticlization conjugated polymer (INCP) (P18) 하였고 산 처리한 결과 polythiophene nano dot을 형성하는데 성공하였다.
Alternative Abstract
Herein, we report a novel synthetic route for conjugated rod coil block
copolymers from the coil type macroinitiator. Initially, polystyrene was prepared
by atom transfer radical polymerization, and its end group was converted to aryl
iodide to be used as the macroinitiator for RuPhos Pd catalyzed Suzuki Miyaura
catalyst transfer polycondensation (SCTP). A fter that, with this PS macroinitiator
P1 )), SCTP of MIDA functionalized 3 hexylthiophene monomer M1 afforded
polystyrene block poly(3 hexylthiophene) P2 with control over molecular
weight and low dispersity. Furthermore, we carried out the same polyme rizations
using other types of coil type macroinitiators including poly(methyl acrylate) P3 )
and poly(methyl methacrylate) P5 )), and this also resulted in corresponding
conjugated rod coil block copolymers with low dispersity. Moreover , with the
developed method, we synthesized a unique ABC type triblock copolymer P10
that was hard to be obtained by previous polymerization protocols. After that,
we report a more sucessful synthetic route for rod coil block copolymers by
bifunctional initiator (Ini1). Thi s route offers coil type macroinitiators (PMMA,
P14 ) that have a high end group fidelity. We sucessfully synthesized a rod coil
block copolymers (PMMA b P3HT, P15 ) via SCTP using P14 . Finally, we synthesized bifunctional acetal initiator (Ini2). Then, poly styrene ( P17 ) was prepared by ATRP. The coil type macroinitator ( P17 ) was conducted SCTP and in situ nanoparticlization of conjugated polymers (INCP). Then we got polystyrene(PS) b polythiophene (PT) ( P18 ) and nano PT dot by deprotection of acetal group.
