In order to improve encapsulation efficiency, gradual coating sometimes solve the problem of substance saturation incorporated in a one thin film layer. I request an article for this issue if it is available.
1. Multilayer silica-methacrylate hybrid coatings prepared by sol–gel on stainless steel 316L: Electrochemical evaluation
Damián A. Lópeza, Nataly C. Rosero-Navarrob, Josefina Ballarrea, Alicia Duránb, Mario Apariciob, Silvia Ceréa,
Surface and Coatings Technology; Volume 202, Issue 10, 15 February 2008, Pages 2194–2201
2. SPIE Proceedings | Volume 3557 | Optical Materials and Thin Film Techniques
Multilayer silica optical coatings by sol-gel process by Hui Wei ; Lin Pang ; Hong Xiao ; Lurong Guo ; Yongkang Guo
3. Multilayer Deposition of Silica Sol–Gel Films by Electrochemical Assisted Techniques Gianmarco Giordano†, Christian Durante‡ , Armando Gennaro‡ , and Massimo Guglielmi*† † Dipartimento di Ingegneria Industriale, Università di Padova, Via Marzolo 9, 35135 Padova, Italy, ‡ Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131 Padova, Italy
J. Phys. Chem. C, 2016, 120 (50), pp 28820–28824
4. BULLETIN OF THE POLISH ACADEMY OF SCIENCES TECHNICAL SCIENCES Vol. 53, No. 3, 2005 Sol-gel technology for biomedical engineering H. PODBIELSKA∗ and A. ULATOWSKA-JARZA˙ Bio-Optics Group, Institute of Physics, Wrocław University of Technology, 27 Wybrzeze Wyspia ˙ nskiego Str., 50-370 Wrocław, Poland