Enhanced crystallization by the virtue of the complete confinement of a ultrathin poly(3-hexylthiophene) film during the patterning process

During the patterning process of conjugated polymers, confinement plays a crucial role in determining the success of a patterned structure; thus, the confinement effect has attracted significant attention. Herein, we have employed the nanoimprinting lithography technique to fabricate nanograting pattern structure on the surface of poly(3-hexylthiophene) (P3HT) ultrathin film and then investigated the effect of confinement on crystallization in detail, which indicates that a uniform and periodic nanograting structure has obviously gained on the film surface and the dimensions of the nanograting structure (width, depth, and period) have matched accurately with the template. Based on the film with two layers, PVPh layer beneath the P3HT layer is also patterned and finally, each line pattern is isolated. Thus, we note it as a complete confinement process. Furthermore, enhanced crystallization can be induced by the patterning process based on the complete confinement condition. However, the crystallization of the P3HT nanograting film under partial confinement is more diminished than that under complete confinement. Therefore, confinement plays an important role in the enhanced crystallization of the P3HT molecule during the patterning process. This investigation of enhanced crystallization under confinement will provide new understanding and guidance for the topographical structure and molecular crystallization of conjugated polymers.