Carbon nanotubes (CNTs) are cylindrical structures made of sp -bonded carbon atoms with diameters ranging from 0.7 to 100 nm and lengths up to several micrometres. CNT membranes consist of aligned or randomly oriented CNTs forming a network of nanopores that enables selective transport of molecules. CNT membranes have several advantages over conventional membranes, such as high permeability, low fouling, high thermal and mechanical stability, and tunable selectivity. They have attracted considerable attention for various applications, such as water treatment, desalination, chemical separation, and energy storage . However, CNT membranes are also susceptible to environmental degradation, such as plasma induced damage, chemical degradation, or microbial growth which can compromise their performance and durability, especially in harsh environments. Degradation can lead to a changes in the effective pore size, or changes to other properties of the membrane. One possible way to protect CNTs from external damage and improve their performance is to coat various materials onto CNTs that can enhance their durability and functionality in harsh environments. For example, costing with metal oxides such as TiO2, Al2O3, ZnO, or NiCoO2 onto CNTs can enhance their anti-fouling and anti-oxidation capabilities, as well as impart photocatalytic, hydrophobic or electrochemical properties. Depositing polymer layers can modify the electrical and thermoelectric properties, and it also holds promise for biotechnological applications. Deposition of nanomaterials, such as graphene, gold, nanodiamond, or fullerene, can enhance the photoelectrical, electrical, thermal, and mechanical properties of CNTs, and enable new applications, such as sensors, electromagnetic shields, electrodes, or electrochemical material. Although capping or surface modification of CNTs with thin films or nanoparticles of various materials has been proposed to protect and functionalize CNTs, depositing materials uniformly around CNTs in a free-standing membrane structure is challenging due to their highly complex 3D morphology. The thickness of the deposition must be meticulously regulated to ensure that the CNT pores remain unobstructed and to achieve uniform surface coverage. The standard film deposition technique for highly conformal thin film deposition onto topographically complex surfaces is atomic layer deposition (ALD), which is based on sequential, self-limiting surface chemical reactions.