Deposition of Aminomalononitrile-Based Films: Kinetics, Chemistry, and Morphology

Abstract

In the last few years, the development of versatile coating chemistries has become a hot topic in surface science after the discovery that catecholamines can lead to conformal coatings upon oxidation from aqueous solutions. Recently, it was found that aminomalononitrile (AMN), a molecule implicated in the appearance of life on earth, is an excellent prototype of novel material-independent surface functionalizing agents leading to conformal and biocompatible coatings in a simple and direct chemical process from aqueous solutions. So far, very little insight has been gained regarding the mechanisms underlying coating deposition. In this paper we show that the chemical evolution of AMN film deposition under slightly basic conditions is different in solution and on silica. Thereon, the coating proceeds via a nucleation process followed by further deposition of islands which evolve to produce nitrogen-rich superhydrophilic fibrillar structures. Additionally, we show that AMNbased material can form films at the air-solution interface from unshaken solutions. These 2 results open new vistas into the chemistry of HCN-derived species of potential relevance in materials science.

A dual perspective on the microwave-assisted synthesis of HCN polymers towards the chemical evolution and design of functional materials

“…S1). In addition, when AMN is used as a precursor of HCN-derived polymers, the pH values of the final suspensions decrease with the reaction time 11 . Therefore, the assisted-microwave NH 4 CN polymerization under anoxic conditions seems to be a much more complex process than those polymerizations performed through a classical procedure.…”

“…Moreover, these prebiotic polymers have recently inspired new coatings for potential biomedical and materials science applications [2][3][4] , such as bone contacting 5 , antibacterial coatings 6 or passive filtration for stormwater/greywater disinfection 7 , and a new family of photocatalysers for the purification of wastewater 8 . On the other hand, the structural properties of these HCN polymers (and hence their potential applications) as well as the single biomolecules and related organics found in them via chromatographic analysis all depend directly on the synthetic conditions used for their production [9][10][11][12][13] . However, despite the considerable developments in the area of microwave-assisted organic synthesis and polymerization in recent decades [14][15][16][17] , only one report describes the production of HCN-derived polymers from formamide using microwave radiation 18 .…”

“…Two main polymerization routes can be seen, in addition to side reactions of hydrolysis, oxidation, etc. ; and a wide variety of five-and six-membered nitrogen heterocycles are postulated, as it is described in detailed in the reference 10,11 .…”

“…Other types of nanofibres were identified in HCN-derived polymers. In coated silica produced from the spontaneous aqueous polymerization of AMN 11 , and from the pyrolysis of formamide at 200 °C 8 , which were not so longer. Together with these nanofibres, a set of nanoparticle rice shapes were also observed ( Fig.…”

One pot protein assisted deposition of pyrocatechol based functional films

“…Even before the time of rational comprehension of phenomena occurring at interfaces, coatings based on polyphenols like urushiol were developed in China 5000 years ago and allowed to preserve the glance of ceramics made that time up to today [1]. After a time during which surface functionalization oriented research aimed to develop specific coatings [2,3] allowing fine control of film thickness, with a sub-monolayer control but at the prize of surface specificity, interest is now focusing on molecules like polyphenols [4,5] catecholamines, molecules having played a potential role in prebiotic chemistry [6,7] to develop versatile and multifunctional coatings at the expense of a lower precision in the film thickness control but with the advantage of using water as the exclusive solvent and bio-inspiration based on rational unravelling of mechanisms developed by living organisms. For instance, the now very popular "polydopamine" based films -adhering on the surface of all known classes of materials-have been developed after having understood that the strong under water adhesion of mussels to stones, wood, polymers…is due to a family of proteins rich in L-DOPA (3,4-dihydroxyphenylanaline) and in L-Lysine [8].…”