Self-Assembly of Rod?Coil Diblock Copolymers within a Rod- Selective Slit: A Dissipative Particle Dynamics Simulation Study

摘要

Dissipative particle dynamics simulations are performed to investigate the self-assembly of rod?coil diblock copolymers R_N_RC_(N?N)_R within a rod-selective slit. The self-assembled structure of the confined system is sensitively dependent on the rigidity k_θ and the fraction f _R of the rod block and the slit height H. From the phase diagram of structures with respect to k_θ and f _R for N = 12 and H = 6, we observe four main structures including disordered cylinder (DC) structure, hexagonally packed cylinders (HPC) perpendicular to the slit surfaces, and lamellar structures parallel (L_||) and perpendicular (L_⊥) to surfaces. And structure transitions can be achieved by tuning k_θ. The effect of the slit height on the self-assembled structure is also studied for R_6C_6 and R_7C_5 copolymers with large k_θ. For R_6C_6, different structures near surfaces and in the interior of slit are observed in relatively wide slits. Whereas for R_7C_5, L_⊥ structure, whose lamellar domain spacing decays exponentially with H, is generally generated. Our results suggest an effective way to control the ordering of rod?coil diblock copolymers under nanoscale confinement.