**7. CO2-philic surfactants**

Like conventional surfactants, the surfactants of carbon dioxide phallic are pure amphophilic compounds but rather than lipophilic and hydrophilic parts, they are made up of carbon dioxide-phobic fragments and carbon dioxide philic. Usually the ends of these surfactants are attracted toward CO2, and are known as the surfactants of CO2-philic segments, and CO2-phobic parts are head group of the surfactant [22]. Phobic segments of carbon dioxide are usually selected as a traditional group of hydrophilic, formerly we have identified the segment of tail of the carbon dioxide-philic surfactant. The distinctive form of a carbon dioxide philic surfactant is illustrated in **Figure 4**.

**Figure 4.** *Structure of a CO2-philic surfactant.*
