Controlling Thermal Effects on Chemical Systems

Thermal energy is present everywhere and is a common cause of failure in many sensitive chemical, biological, and mechanical systems. Many methods of controlling thermal effects by protecting against its harmful effects or by harnessing it for conversion to another form of energy to do useful work have been developed. In particular, protection of thermally sensitive proteinaceous therapeutics such as vaccines requires protection against thermal energy in order to retain their therapeutic relevance. The current “cold chain” infrastructure in place that keeps them refrigerated throughout their journey from factory to clinic are expensive and prone to failure, costing billions of dollars annually and a large amount of wasted drugs. Herein, methods of encapsulating proteinaceous materials within the metal-organic framework ZIF-8 are developed and explored in their encapsulation ability, thermal and chemical protection ability, in vivo therapeutic effectiveness, and general protein affinity. Another mode of controlling thermal energy is by using it to fuel crystallographic phase transitions to produce thermosalient effects. These dynamic crystals form a class of molecular solids capable of converting thermal energy into mechanical motion. Herein, metallized single crystals of decoxyphenyl N-substituted naphthalenediimide are used to take advantage of a reversible large negative change in length upon heating past its phase transition to form a reusable thermally triggered crystal switch. These methods of controlling thermal effects show promising potential to positively affect the fields of chemistry, biology, electronics, and materials science.