Synthesis of Double Side-Chain Liquid Crystalline Block Copolymers Using RAFT Polymerization and the Orientational Cooperative Effect

Abstract

We report on the synthesis and characterization of a new type of diblock copolymer that is composed of two side-chain liquid crystalline polymers (SCLCP1-block-SCLCP2). The diblock copolymer of poly{6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate}-block-poly{6-[4-(4-cyanophenyl)phenoxy]hexyl methacrylate} (PAzoMA-b-PBiPMA) was successfully synthesized using the reversible addition-fragmentation chain transfer (RAFT) polymerization. Low-polydispersity samples of various compositions can be prepared using either PAzoMA or PBiPMA macromolecular chain transfer agent. We show that the orientational cooperative effect can be effective even in microphase-separated samples due to the interaction of the two mesogens via the interface. Indeed, the photoinduced orientation of azobenzene groups on the PAzoMA block can bring biphenyl groups on the PBiPMA block to orient in the same direction inside their respective lamellar domains. While RAFT can be used to access to double or all-SCLC block copolymers, this study also demonstrates the potential interest of exploring the interplay of the LC order of different SCLCPs within a microphase-separated system.

Photocontrollable Liquid‐Crystalline Actuators

“…[ 9 , 171-173 ] Starting from commercially available PEO, Yu et al applied this approach to prepare several well-specifi ed triblock copolymers with excellent photocontrol performances, as shown in Figure 17 . [ 173 ] In addition to ATRP, other controlled radical polymerization techniques such as reversible addition/fragmentation chain transfer polymerization (RAFT) [ 174,175 ] and nitroxide-mediated polymerization (NMP), [ 176 ] have also been explored to synthesize photoresponsive LCBCs. Moreover, LCBCs can also be prepared by post functionalization of active groups in BC precursors.…”

Photoinduced Microphase Separation in Block Copolymers: Exploring Shape Incompatibility of Mesogenic Side Groups

“…The azo double-SCLC BCP was synthesized by using the reversible addition-fragmentation chain transfer polymerization method (RAFT) [11] Details on the synthesis and characterizations of the polymers are given in the Supporting Information.…”

Light‐Responsive Block Copolymers

“…Latter on, studies comparing the structure and photochromic behaviors of azobenzenes in homo and block copolymer films were published. [58][59][60][61][62][63][64][65][66] Azobenzene J.-M. Schumers, C.-A. Fustin, J.-F. Gohy Figure 11.…”