Layer-by-layer self-assembly for carbon dots/chitosan-based multilayer: Morphology, thickness and molecular interactions

Oxidized Carbon dots, prepared from the acid dehydration of cellulose, were used in the preparation of self-assembled films with the biopolymer chitosan. The morphology, thickness and molecular interactions of the films were characterized with a variety of techniques including AFM, FTIR, UV–Vis and Surface Plasmon Resonance (SPR) spectroscopy. We noticed an increase in the thickness of the bilayers with increasing ionic strength and pH provided by the increase of the amount of CD and chitosan deposited in each cycle. This increase was mainly due to higher flexibility of the biopolymer on these conditions and to the formation of agglommerates of carbon dots in high ionic strength. On the other hand, the greater flexibility together with the higher adsorption have generated films with smoother morphology due to the higher coating on the spherical particles. The results described here suggest that the structure of the film, i.e., morphology and thickness can be easily controlled and reproduced, by controlling the conditions of the biopolymer and CD solutions, in addition to the traditional number of dips. Finally, the prepared films have potential application in the development of imunosensors, functional coatings, surface photoactive and UV protection films.

Publication year: 2017
Authors: T. da S.Pinto a, L.A. Alves a, G. de Azevedo Cardozo a, V.H.O. Munhoz a, R.M. Verly a, F.V. Pereira b, J.P. de Mesquita a

a – Department of Chemistry, Federal University of the Jequitinhonha and Mucuri Valleys, Rodovia MGT 367 – Km 583, nº 5000, Alto da Jacuba, CEP 39100-000, Diamantina, MG, Brazil
b – Department of Chemistry, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, CEP 31270-901, Brazil

Published in: Materials Chemistry and Physics, Vol. 186 (2017), p. 81–89
DOI: 10.1016/j.matchemphys.2016.10.032


adsorption AFM altering ionic strength altering pH bilayer chitosan dip coating layer-by-layer oxidized carbon dots refractive index self-assembled layer SiO2 (silicon dioxide) sensor slide thickness UV protection films


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