Publications by authors named "D M DeLongchamp"
The distribution of counterions and dopants within electrically doped semicrystalline conjugated polymers, such as poly(3-hexylthiophene-2,5-diyl) (P3HT), plays a pivotal role in charge transport. The distribution of counterions in doped films of P3HT with controlled crystallinity was examined using polarized resonant soft X-ray scattering (P-RSoXS). The changes in scattering of doped P3HT films containing trifluoromethanesulfonimide (TFSI) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (FTCNQ) as counterions to the charge carriers revealed distinct differences in their nanostructure.
View Article and Find Full Text PDFHierarchical structure-within-structure assemblies offer a route toward increasingly complex and multifunctional materials while pushing the limits of block copolymer self-assembly. We present a detailed study of the self-assembly of a series of fluorinated high-χ block copolymers (BCPs) prepared via postmodification of a single poly(styrene)--poly(glycidyl methacrylate) (S--G) parent polymer with the fluorinated alkylthiol pendent groups containing 1, 6, or 8 fluorinated carbons (termed trifluoro-ethanethiol (TFET), perfluoro-octylthiol (PFOT), and perfluoro-decylthiol (PFDT), respectively). Bulk X-ray scattering of thermally annealed samples demonstrates hierarchical molecular assembly with phase separation between the two blocks and within the fluorinated block.
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- Physical vapor deposition (PVD) can create organic glasses with specific molecular orientations, but the effects of the interface on structure and stability are not well understood, presenting a knowledge gap in the field.
- Polarized resonant soft X-ray reflectivity (P-RSoXR) is used to analyze the molecular orientation and composition of a bilayer film made from DSA-Ph on Alq3, revealing that the DSA-Ph molecules align parallel to the Alq3 interface before transitioning to their bulk orientation.
- The study shows a correlation between the interface orientation and the bulk behavior of similar composite glasses, providing a method for predicting molecular orientation at interfaces, which is vital for advancing
Article Synopsis
- - Polarized resonant soft X-ray scattering (P-RSoXS) is a cutting-edge technique that helps analyze the molecular orientation and chemical makeup of soft materials like polymers and biomaterials through X-ray scattering and spectroscopy.
- - A new open-source virtual instrument has been developed to simulate P-RSoXS patterns using powerful GPUs, significantly speeding up the process and handling complex sample properties at nanoscale levels.
- - This new framework dramatically enhances simulation speed (over 1000 times faster than existing software) and simplifies user interaction by integrating with Python, making it easier for researchers to explore, analyze, and apply the data in various scientific applications.
The ability to control structure in molecular glasses has enabled them to play a key role in modern technology; in particular, they are ubiquitous in organic light-emitting diodes. While the interplay between bulk structure and optoelectronic properties has been extensively investigated, few studies have examined molecular orientation near buried interfaces despite its critical role in emergent functionality. Direct, quantitative measurements of buried molecular orientation are inherently challenging, and many methods are insensitive to orientation in amorphous soft matter or lack the necessary spatial resolution.
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