Mobile liquid-substrate for self-assembly of solution-processable poly (5-aminoindole) by Langmuir technique

Abstract

Polymers based device performance greatly depends on the π-backbone chain orientation along the charge transportation direction. Therefore, rearrangement of polymer chains at molecular level and thin film fabrication via Langmuir technique is highly desirable for large area electronic device applications. Here, we have utilized air-water interface of Langmuir technique for proper molecular orientation of the interfacially (water-chloroform interface) synthesized, electroactive poly (5-aminoindole) (5-APIn). 5-APIn is assembled over aqueous (mobile) subphase and variation in film compactness with varying surface pressure has been plotted as surface-pressure per area (п-A) isotherm. The films fabricated via Langmuir-Schaefer (LS) technique at surface pressures 35, 45 and 55 mN/m are qualitatively investigated using scanning electron microscopy (SEM). Surface roughness of the 5-APIn LS film is also investigated via atomic force microscopy (AFM). Polymer ordered assembly obtained in LS film is compared to bulk via Raman spectroscopy. Further, we have explored its large area electronic application via Al/5-APIn LS film/ITO diode configuration. Our study illustrates the significant role of mobile liquid substrate in formation of large area, smooth and ordered LS film of 5-APIn that unlocks its way for utilization in low cost and large area display electronic applications.