Over time PAANY-acyl is deacetylated giving rise to the reappearance of colloidal clusters (40% aggregation at 90 min and 50% aggregation at 180 min). Conditions: PAANY 0.7 mM, pyridine 1.75 mM, imidazole 1.75 mM, acetic anhydride 14 mM in borate buffer (pH 9.0 200 mM) with silica microspheres (diameter= 1 µm). The standard deviation between two samples is shown (n=2). The point measured at t=0 min is a different sample without fuel addition, but all other conditions the same. The scale bar in all images is 10 µm. The aggregation (%) was determined by using Matlab.