Foaming properties of the synthesised imidazolium acetate salts carried out via a Bartsch foaming testa.
| Compound | Foam height/[cm (pH)] | Notes | Bubble size | |
|---|---|---|---|---|
| Acidic range | Basic range | |||
| SDS | 26–22 (2–3), 36–33 (5) | 14–10 (12) | Readily dissolved, very stable dense foam | S, M |
| [C8C8IM][OAc] | 15–6 (2) | 7–2 (8–9), 9–2 (12–13) | Readily dissolved, pale yellow solution, weak sparse foam | S |
| [C10C10IM][OAc] | 60–56 (1–2) | 47–45 (9), 40–30 (13) | Readily dissolved, pale yellow solution, stable dense foam | S, M, L |
| [C12C12IM][OAc] | 27–24 (1–2) | 27–25 (8), 27–24 (13) | Slowly dissolved, yellow solution, highly stable dense foam | S |
| [C14C14IM][OAc] | 4–4 (1) | 4–4 (8, 4–4 (13) | Partially dissolved, sparse foam with particulate | S |
a
Foamability and foam stability were determined via the use of a 100 mL measuring cylinder (vide ESI Analytical procedure 3). The foam height immediately after shaking and after a minute are herein reported side by side. pH adjustment was done via addition of 5 to 10 drops of either NaOH (1 M) or HCl (1 M). Sodium dodecyl sulfate (SDS) was used as reference compound. Bubble size is registered as small (S), medium (M), and large (L). The test was carried out on 40 mL aqueous solutions with 0.1% w/w of the tested surfactant dissolved within it.