PG and VG serve as the primary solvent carriers, constituting up to 90% or more of the e-liquid volume. Their physical and chemical differences profoundly affect the flavor experience.
挥发性：PG has a lower boiling point ($\approx 188^{\circ}\text{C}$) and a higher vapor pressure compared to VG. This higher volatility means it readily vaporizes at lower temperatures, leading to a味道释放更尖锐、更强烈、更快加热时。它还造成明显的“喉咙撞击”感觉。
蔬菜甘油（VG）：
微观结构：VG is highly viscous, has a higher molecular weight, and contains an additional hydroxyl ($\text{OH}$) group, leading to更强的分子间氢键。这种更高的粘度和更大的甜度有时可以“静音”或抑制微妙的风味通过物理减慢风味分子的扩散并巧妙地干扰味觉受体。
挥发性：VG has a higher boiling point ($\approx 290^{\circ}\text{C}$) and a lower vapor pressure. It is less volatile than PG, resulting in a slower vaporization rate and the production of更稠密的气溶胶云.
结构-功能分析：Flavor chemists often favor compounds with high molecular weight, low vapor pressure, and chemical structures that are less susceptible to bond cleavage at typical vaping temperatures ($100^{\circ}\text{C}-250^{\circ}\text{C}$). Utilizing compounds from known, stable chemical classes, such as certain esters or stable aromatic structures, minimizes the risk of unintended transformation.
温度和光照控制：Flavors are best stored in cool, dark environments ($\approx 15^{\circ}\text{C}-21^{\circ}\text{C}$) to minimize the rate of oxidation and thermal-induced reactions. Storing e-liquids in the dark and at cold temperatures can significantly improve the stability of flavorings over time. (Chen et al.,电子烟液中调味化学品的稳定性：超过 24 个月的自然产品老化研究，2024）。
