Effects of chemical structure on the dynamic and static surface tensions of short-chain, multi-arm nonionic fluorosurfactants

• Synthesis of novel multi-arm, short chain nonionic fluorosurfactants is presented.
• Static and dynamic surface tensions are characterized by ring and maximum bubble pressure tensiometry.
• Fluorosurfactant chemical structure and dynamic and static properties are correlated.
• Branched systems can be used to substitute long chain fluorosurfactants.
• Saccharide-based surfactants highlight the importance of the hydrophilic block on the fluorosurfactant properties.

Fluorinated surfactants with short perfluoroalkyl chains (RF) as potential substitutes for the environmentally questionable, long RF systems are presented. Three types of nonionic hydrophilic-fluorophilic amphiphiles are synthesized and evaluated based on surface activity in equilibrated (static) and non-equilibrated (dynamic) states. Furthermore, several mono- and disaccharide-based fluorosurfactants are also examined as potential non-bioaccumulative alternatives. A correlation between the chemical structure and resulting surface properties is made by comparing RF length, number and size, alkyl-spacer, and hydrophilic moieties. Based on dynamic and static surface tension experiments, the effects of surfactant structure are summarized to provide a basis for the future design of fluorosurfactants. We have found that surfactants with more perfluorinated chains tend to have a higher surface tension reduction, but typically result in slower dynamic behaviors. Using the presented structural characteristics, surfactants with RF < 4 can be prepared with static surface tensions as low as 18.1 mN/m or reduce surface tension within milliseconds.

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