Precise and nondestructive characterization of a ‘buried’ nanostructure in a polymer thin film using synchrotron radiation ultra-small angle X-ray scattering

Abstract

Nanoimprint lithography (NIL) is a simple and high-resolution patterning method. Nanoimprinted structures can be fabricated not only as surface structures but also as 'buried' structures for applications such as electro-optical devices. However, a precise and nondestructive evaluation method for nanoimprinted structures has not yet been established. Synchrotron radiation ultrasmall angle X-ray scattering (SR-USAXS) is a nondestructive and high-resolution characterization method. In this study, we fabricated nanostructures on a poly(lactic acid) (PLA) film using NIL. In addition, the nanoimprinted PLA film was covered with a polystyrene thin film to fabricate a 'buried' structure. The fabricated surface and the 'buried' structure were evaluated using SR-USAXS. The scattering pattern was clearly obtained from the surface and the 'buried' structure. The size of the 'buried' structure, which was estimated from the diffraction pattern, was in good agreement with that of the surface structure. These results indicate that SR-USAXS is powerful tool for the nondestructive and precise characterization of surface and 'buried' structures.

“Buried” nano-structure and molecular aggregation state in ordered heterojunction poly(3-hexylthiophene)-based photovoltaics

“…To estimate the chain orientation, measurements were performed with the X-ray beam oriented parallel and perpendicular to the line pattern. [16][17][18][19][20][21][22][23][24] To improve angular resolution, a soller slit was installed in front of the detectors. The divergence angle was determined to be 0.099°.…”

“…The anisotropic scattering spots are attributed to the periodic structure of the surface for NI_P3HT and the "buried" nano-structure for PCBM/NI_P3HT, respectively. 18,19) The periodic distance, d, was estimated using…”

“…The structural parameters were estimated by analyzing the diffraction intensity profile. The scatterer can be modeled as the convolution of onedimensional rectangular grating model 19) and Gaussian distribution, as shown in Fig. 4.…”

“…Recently, we showed that synchrotron radiation small angle X-ray scattering (SR-SAXS) is a powerful tool to characterize "buried" nanostructures. 18,19) Here, the morphology and interdigitization at the P3HT/PCBM interface is investigated using SR-SAXS. The chain orientation and crystal structure of the OHJ-OPV was confirmed by grazing incidence X-ray diffraction (GIXD).…”

Processing and characterization of bio‐based poly (hydroxyalkanoate)/poly(amide) blends: Improved flexibility and impact resistance of PHA‐based plastics

“…The use of petroleum‐based plastics for products and packaging has become ubiquitous in industry, a trend that is contributing heavily to ecological problems such as increased CO 2 levels, pollution of land and waterways, and overloading of the solid‐waste stream. Although petroleum plastics are extremely versatile and fulfill the performance requirements for a multitude of applications, increasing public awareness of their environmental impacts has spurred efforts to replace petroleum feedstocks with sustainable and ecofriendly alternatives . Motivated by the goal to reduce our carbon footprint and dependence on fossil carbon sources, bio‐based polymers and composites are becoming widely utilized in polymer manufacturing and medical applications .…”