The novel concept and significance of a nano-alloyed polymer, which includes nano-dispersed domains, is proposed, and a biaxially stretched nano-alloyed film is developed. The developed film has a higher glass transition temperature and improved dimensional stability compared with regular poly(ethylene terephthalate) (PET) films. Nano-sized polyimide domains are dispersed with our original melting extrusion process, which produces highly concentrated polyimide master batches at much lower temperatures than the regular processing temperature of the polyimide. The biaxially stretched film has been industrialized for use as a substrate for data storage tapes and can additionally be applied to materials in the fields of electronic devices, automobile, environmental and energy devices. Polymer Journal (2012) 44, 1170-1178; doi:10.1038/pj.2012.96; published online 13 June 2012Keywords: biaxially stretched film; glass transition temperature; nano alloy; nanostructure control technology; polyester; polyimide INTRODUCTION Development of a biaxially stretched nano-alloyed film Biaxially stretched polyester films, which are represented by poly (ethylene terephthalate) (PET) films, are currently the most widely used polymeric substrate materials in the fields of display technologies, electronic devices, storage media, electronic insulators, automobile, molding, package, printing and architecture. This widespread use is a result of the films possessing high strength, durability, transparency, flexibility and good surface properties. Information and telecommunications equipment have recently required more compactness and portability as well as excellent film properties, such as higher heat resistance and dimensional stability, especially in the field of electronics, environment and energy. It has been difficult for conventional biaxially stretched PET films to meet the future demand, and outstanding films with cost effectiveness are required.We have created a biaxially stretched nano-alloyed PET film that has a higher glass transition temperature, which is an intrinsic property of polymers, compared with regular biaxially stretched PET films. 1 The technical points from our development are the following. First, the novel concept and significance of nano-alloyed polymers have been proposed. Secondly, nanostructure control technology has been developed for the nano-sized dispersion of polyimide, which is a different organic polymeric material than polyester. Finally, the processing conditions for the biaxially stretched nano-alloyed films have been established. In this paper, we describe the design of a nano-alloyed polymer and biaxially stretched films.

We prepared a rod-like amphiphile with a molecular recognition end group, alpha-helical and hydrophobic poly(gamma-methyl L-glutamate) (PMG) containing hydrophilic beta-cyclodextrin (CyD) as an active end group (PMG-CyD), and formed its monolayer at the n-hexane/water interface. The interfacial pressure (pi)-area (A) isotherms of the monolayer showed that alpha-helix rod of PMG-CyD could be vertically oriented at the oil/water interface, facing the hydrophilic terminal CyD group to the water phase, by increasing the interfacial concentration of the polypeptide. Under the condition 2-p-toludinyl-naphthalene-6-sulfonate (TNS), an intimate guest molecule for the CyD in water was introduced into the water phase beneath the monolayer. Within a minute the monolayer began to oscillate which could be monitored by the rhythmic response of the interfacial pressure of the monolayer. The oscillation continued over ten minutes and then terminated. The mode of the oscillation was found to change with time, i.e., the initial stage showing a periodic sharp reduction in the interfacial pressure (period I), the second stage having sharp increase in the pi value (period II), and the last stage of irregular oscillations (period III). The Fourier analysis of each period also supported the three stages during the oscillatory process. It was also found that when the alpha-helix rod of PMG-CyD lay down in the monolayer, the guest TNS did not induce any changes in the interfacial tension. This nonlinear rhythmic interfacial phenomenon was explained in terms of the periodic movement of the PMG-CyD monolayer resulting from the binding and releasing of the guest TNS across the oil/water interface. (c) 1999 American Institute of Physics.

A rod-like amphiphile, hydrophobic poly(γ-methyl l-glutamate) containing β-cyclodextrin as a hydrophilic terminal group (PMG-CyD), lay down in its monolayer membrane at air/water interface, however, it has a possibility for the perpendicular orientation at hexane/water interface above specific surface pressure.