Ozone layer upper-atmosphere ozone-depletion rate slowed down significantly during the previous decade. Some breakdown can be expected to continue because of ODSs used by nations which have not banned them, and because of gases which are already in the stratosphere. Some ODSs, including CFCs, have very long atmospheric lifetimes, ranging from 50 to over 100 years. It has been estimated that the ozone layer will recover to 1980 levels near the middle of the 21st century. A gradual trend toward "healing" was reported in 2016. Compounds containing C–H bonds (such as hydrochlorofluorocarbons, or HCFCs) have been designed to replace CFCs in certain
Layer by layer assembly technique. By the fact that each bilayer can be as thin as 1 nm, this method offers easy control over the thickness with 1 nm resolution. LbL has found applications in protein purification, corrosion control, biomedical applications, ultrastrong materials, and many more. LbL composites from graphene oxide harbingered the appearance of numerous graphene and graphene oxide composites later on. The first use of reduced graphene oxide composites for lithium batteries was also demonstrated with LbL multilayers. Layer by layer Layer-by-layer (LbL) deposition is a thin film fabrication technique. The films are formed by depositing alternating layers of oppositely charged