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Date of Award
Bachelor of Science (BS)
Department of Physics and Astronomy
Aqueous foams can be described as a close packing of gas bubbles stabilized by surface active molecules. Their complex and diverse properties make them attractive for many chemical and physical applications where foaming, emulsifying or coating processes are needed. The recent synthesis of multi-cephalic and multi-tailed amphiphilic molecules have reportedly enhanced their antibacterial activity in connection with tail length and nature of the head group.
This report covers the foamability of two triple head, double tail cationic surfactants (M-1,14,14, M-P,14,14) and a triple head single tail cationic surfactant (M-1,1,14) and compares them with commercially available single headed, single tailed anionic and cationic surfactants (SDS, CTAB and DTAB). Additionally, a longer tailed variant (M-1,16,16) was also tested.
The results show that bubble rupture rate decreases with the length of the carbon chain, irrespective of head structure. For the longer tailed variant (M-1,16,16) foam was difficult to produce leaving it untestable. The growth rate of bubbles with short tailed surfactants (SDS) and longer, single tailed tricationic surfactants (M-1,1,14) was shown to be twice as high as those with longer tailed surfactants (CTAB, M-P,14,14, M-1,14,14). This fact was related to the size variation of bubbles, where the foams made with short tail surfactants exhibited higher polydispersity than those with short tails. This suggests that foams with tricationic amphiphilics are closely linked to their tail length and generally insensitive to their head structure.
Heerschap, Seth A., "Aqueous Foam Stabilized by Tricephalic Amphiphilic Surfactants" (2015). Senior Honors Projects, 2010-current. 104.