Morphology determination of defect-rich diblock copolymer films with time-of-flight grazing-incidence small-angle neutron scattering

Abstract

The complex nanomorphology of a defect‐rich deuterated poly(styrene‐block‐methyl methacrylate), P(S‐b‐MMAd), diblock copolymer film is determined with a combination of grazing‐incidence small‐angle neutron scattering (GISANS) and time‐of‐flight (TOF) mode. TOF‐GISANS enables the simultaneous performance of several GISANS measurements that differ in wavelength. The resulting set of GISANS data covers different ranges of the scattering vector and has different scattering depths. Thus surface‐sensitive and bulk‐sensitive measurements can be performed simultaneously. The P(S‐b‐MMAd) film exhibits a lamellar microphase separation structure, which because of the defects is arranged into small, randomly oriented grains, composed of four–five lamellar repetitions. In the near‐surface region, the lamellar structure is oriented parallel to the substrate, which explains the smooth surface found with atomic force microscopy.

Influence of Solvent Additive 1,8‐Octanedithiol on P3HT:PCBM Solar Cells

“…Four different neutron wavelengths (0.37, 0.45, 0.67, and 0.99 nm) are selected from the total neutron wavelength band (0.20–1.48 nm) for this figure. The overall intensity varies with the neutron wavelength due to the distribution of the intensity of the incoming neutrons . Each 2D pattern is divided by the horizon (indicated by a dashed line in Figure a) into two parts: Below the horizon the transmitted signal is located and above the horizon the reflected signal is probed.…”

“…Grazing incidence small‐angle neutron scattering (GISANS) has shown great success in probing the inner nanomorphology in a large sample volume . In combination with the time‐of‐flight (TOF) mode, a series of 2D GISANS data obtained under different neutron wavelengths, so‐called time‐of‐flight grazing incidence small angle neutron scattering (TOF‐GISANS), are acquired simultaneously from a single measurement . This advanced technique allows for the investigation of the inner morphology and for a quantitative determination of the molecular miscibility.…”

“…Rawolle et al successfully calculated the porosity of the titania structure and the degree of backfilling of the polymer in the titania pores . In addition, TOF‐GISANS allows simultaneous acquisition of morphological information of the sample surface and the bulk …”

Adhesive–adherent interfaces probed with grazing-incidence small-angle neutron scattering

“…These methods only probe small areas and are limited to surfaces only as long as a nondestructive characterization is desired. In particular, grazingincidence small-angle X-ray and neutron scattering (GISAXS and GISANS) give valuable information about lateral structures (Mü ller-Buschbaum, 2003a, 2012Renaud et al, 2009;Mü ller-Buschbaum et al, 2014;Hexemer & Mü ller-Buschbaum, 2015). Such interfaces have been investigated using methods such as, for example, ultrasonic waves and dielectric spectroscopy to get information about the durability and integrity of bonds (Rokhlin & Marom, 1986;Rokhlin et al, 1993;Boinard et al, 2000).…”

“…An alternative well established approach to structural investigations of polymer films is the use of scattering techniques employing X-rays and neutrons. In particular, grazingincidence small-angle X-ray and neutron scattering (GISAXS and GISANS) give valuable information about lateral structures (Mü ller-Buschbaum, 2003a, 2012Renaud et al, 2009;Mü ller-Buschbaum et al, 2014;Hexemer & Mü ller-Buschbaum, 2015). GISANS is chosen for the present investigation for several reasons: GISANS is a nondestructive method and the large footprint of the neutron beam on the sample (in this study $5 Â 8 cm) ensures a high statistical significance of the obtained results (Mü ller-Buschbaum et al, 2004;Wolff et al, 2005).…”