Cromolyn/gelatin mixtures as aqueous alignment media and utilization of their mechanical stability for a layering technique

• Published in: Magnetic resonance in chemistry 2018-12, Vol.56 (12), p.1176-1182
• Main Authors: Niklas, Thomas, Schulze, Philipp, Farès, Christophe
• Format: Article
• Language: English
• Subjects: Alignment; alignment medium; Anisotropic media; Anisotropy; cromolyn; Gelatin; Liquid crystals; NMR; Nuclear magnetic resonance; polymer‐dispersed liquid crystals; residual dipolar couplings; spatially selective NMR; Stability; Sucrose
• ISSN: 0749-1581; 1097-458X
• DOI: 10.1002/mrc.4786

In this study, aqueous blends of cromolyn and gelatin (“cromogels”) are introduced as anisotropic media. The addition of gelatin enables an advantageous adjustability of the strength, the homogeneity, and the stability of the cromolyn alignment. The mechanical stability of these polymer‐dispersed liquid crystals is further utilized by stacking layers of D2O/cromolyn/gelatin with varying component ratio. The resulting distinct phases with correspondingly different degrees of alignment can be targeted by spatially resolved NMR techniques. As a case study, we investigated sucrose in a two‐phase system with neat D2O and analyte layered over the anisotropic medium. A recently presented spatially selective coupled‐type HSQC experiment allows the determination of one‐bond C‐H splitting in both phases. Aqueous blends of cromolyn and gelatin (cromogels) are introduced as anisotropic media. These polymerdispersed liquid crystal phases show advantageous adjustability of strength, homogeneity, and stability. Stacked layers of D2O/cromolyn/gelatin with varying component ratio allow preparation of phases with different degrees of alignment that can be targeted by spatially resolved nuclear magnetic resonance techniques.