Glass Transition of Ultrathin Sugar Films Probed by X-Ray Reflectivity

Abstract

Besides being the main types of carbohydrate in food, sugars are a representative protectant in biopharmaceutical formulations. To identify the protection mechanism, researchers have extensively investigated the bulk physicochemical properties of sugars. However, whereas the glass transition of sugar has been widely studied and debated, the physicochemical properties of sugar molecules in confined circumstances such as nanometer thick films remain largely unknown. In this chapter, we introduce an experimental procedure for analyzing the glass transition of sugars in ultrathin films. The analysis is based on X-ray reflectivity (XRR) analysis, which has been often applied in glass transition studies of polymer films, but never in sugar media.