Preparation of alkylated carbon dots and their application in heat-not-burn cigarettes†

It is of vital importance to reduce the production of harmful substance involved in the smoke of traditional cigarettes. The solution to this depends largely on the development of a new generation of cigarettes, among which heat-not-burn (HnB) cigarettes have received much attention during the past decade. As HnB cigarettes are normally shorter than traditional ones, there is a pressing necessity to develop additives to improve the performance of currently used cooling materials, which, in most cases, are polylactic acids (PLA). Herein, we prepared a series of carbon dots (CDs) functionalized by peripheral aliphatic chains, which exhibited large enthalpy changes during heating. When blended with PLA, the composites showed improved cooling efficiency characterized by an increased total enthalpy change up to an enhancement factor of ∼6.4. Notably, the introduction of alkylated CDs does not generate additional harmful components upon heating, rendering it a viable cooling solution in HnB cigarettes. This study holds considerable value for optimizing the structure of HnB cigarettes and contributes to advancements in tobacco science and technology.