Lead in the subphase and my lonely bike

Morning all

Yesterday Faridah showed me some samples she had made using lead nitrate (or it might have been acetate) in the water subphase. The monolayer contained a carboxylic acid group that should take up the lead. She used pH of around 7.5 I think. The question is this - the films were frosty in appearance and seemed to contain white crystallites (we're looking down the microscope today to get more info). So you inorganic chemists out there, what might be happening? Could we be precipitating some lead salt or oxide perhaps? If so, would you reckon that exposure to H2S might convert it to the sulphide? It doesn't really matter if the film contains inorganic crystals after deposition so long as they are nanoparticulate (obviously we're seeing large clusters with our eyes); our objective you see is to form nanoparticulate PbS eventually. Any comments very welcome - thanks.

OK, this morning's images are of (i) my bike that is left in the rack at about 6.50am each morning only to be on its own for the whole day. You may think this is an invitation to more bike thiefs but they don't know where it is left and of course I've now booby-trapped it! Have a great day all; (ii) my "Canadian leaf" - I gave this English Maple leaf to a friend and former colleague from Canada - Jamie Forrest - when he worked here in Sheffield way back around the mid-late 90s. When he left he gave it back to me as a keepsake. I've still got it and it's doing well at an age of at least 10 years, maybe more.