Parallel aligned nanostripe arrays in the spreading film of a bolaamphiphile at the air/water interface

In this paper, we report the formation of parallel aligned nanostripe arrays in the spreading film of a bolaamphiphile through the air/water interface. We have found that a bolaamphiphilic tetraethyl ester-di-l-glutamic acid-N,N′-eicosanedioic amide could form a floating film on the water surface, exhibiting a plateau region in the surface pressure–area (π–A) isotherms. When the spreading film was compressed over the plateau region, a parallel aligned nanostripe array was observed. Detailed phase behaviours of the spreading film have been investigated by means of the atomic force microscopy (AFM) of the transferred LB films deposited at the selected surface pressures. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM) and electron diffraction (ED) have been employed to characterize the transferred film and the patterned nanostripes. The formation mechanism of the nanopattern is proposed.