Crystallization tendancy as a function of steric hinderance in novel small molecule glassformers

Authors: Christopher Faherty, Sarah Wolf

SUNY Campus: SUNY Cortland

Presentation Type: Poster

Location: Old Union Hall

Presentation #: 29

Timeslot: Session A 9:00-10:00 AM

Abstract: Amorphous solids, or glasses, are solids in which the particles are randomly arranged. These have different properties than crystalline solids. Glasses play an important role in many industries. For example, they make better pharmaceuticals and have potential applications as more efficient solar cells. Being a glass, however, is not thermodynamically favorable, and glasses crystallize over time. Although it is known these glasses are useful, glass stability is still a heavily researched topic. The subject of this research is to investigate the role of hydrogen bonding and steric hinderance. The goal was to synthesize four glass forming molecules through Suzuki coupling to probe glass forming ability and crystallization tendency under different storage conditions. Glass forming molecules varied in their steric hinderance and hydrogen bonding abilities, results would give researchers information on how these properties affect glass formation and storage under different conditions. Results support the idea that molecular shape, including resulting from rotational barriers (atropisomerism), strongly dictated glass-forming ability. Along with this, atropisomerism supported aging in glasses which led to a more stable formation. Samples were ran using differential scanning calorimetry (DSC) to analyze if the molecules were more likely to form a glass or crystallize. Results showed that molecules with large steric hinderance preferred crystallization. Only two of the desired four compounds were successfully synthesized, and work to investigate the role of hydrogen bonding is ongoing.