Studies of a novel polymerizable amphiphilic dendrimer

In the present study, we have synthesized a polymerizable amphiphilic dendrimer by attaching 10,12-pentacosadiynoic acid (PDA) to a third generation poly(amidoamine) (PAMAM) dendrimer core (PDA-PAMAM). This dendrimer was characterized by 1H NMR and MALDI-TOF mass spectroscopy. The amphiphilic property of this dendrimer has been studied. Surface pressure and surface dipole moment–area isotherm measurements have shown that PDA-PAMAM forms a stable monolayer at the air–water interface with a limiting molecular area of 460 Å2 per molecule. The compressed monolayer can be readily polymerized upon UV irradiation, as like other PDA derivatives. The topography of the monolayer was observed by Brewster angle microscopy (BAM) as well as by the environmental scanning electron microscopy (ESEM). We found a good correlation between the size and shape of monolayer domains observed with the BAM and ESEM techniques. To our knowledge, this is the first time wet mode ESEM has been used to characterize L–B film. The wet mode ensures that L–B films remain intact without being damaged by the high vacuum system of traditional SEM. As a preliminary study, we have found that this new dendrimer forms colloidal particles in chloroform solution and can be readily polymerized by UV irradiation.