Synergistic enhancement in optoelectrical anisotropy of polymer film at the air-liquid interface: An insight into molecular weight distribution dependent polymer alignment

In the context of polymer films, the degree of polymer chain orientation and alignment plays a crucial role in producing a high-performance electronic device owing to its quasi 1D nature. Therefore, a novel investigation on the dependency of optoelectrical anisotropy on polymer molecular weight distribution and its synergistic enhancement at the air-liquid interface was conducted using poly (3, 3′″ dialkylquarterthiophene) (PQT-12). We also explored PQT-12 (2:1), where 2:1 is the ratio by weight of the polymer obtained from hexane and CH₂Cl₂, respectively. In order to understand the mechanism of self-assembly and alignment of different molecular weight polymers at the air-liquid interface, Margonian flow effect was used to obtain oriented and aligned films that were investigated using multiple characterization techniques at the molecular, microscopic, and macroscopic levels. It was found that the film formed using PQT-12 (2:1) demonstrated a synergistic enhancement in dichroism (up to 55%), orientation, and ordering with synergistic enhancement in electrical anisotropy up to 11, mobility upto 11-fold and 2.5 fold respectively as compare to pristine PQT-12 (Hexane) and PQT-12 (CH₂Cl₂) isolated polymer in ambient condition. Thus, our study presents the an insight into the molecular weight distribution dependent alignment at air liquid interface for enhancement in device performance.