Elastic modulus of polyamide thin films formed by molecular layer deposition

Molecular layer deposition (MLD) is a gas-phase deposition technique that can create ultra-thin films with precisely controlled chemical composition and thickness by depositing one monolayer at a time. This makes MLD an attractive technology for desalination membranes among other applications. Given its relatively recent development, little information has been reported regarding the properties of MLD thin films. We present the results of an initial mechanical property study of MLD films with thicknesses ranging from ∼50 to 2000 nm. MLD was utilized to create crosslinked polyamide films grown using either m-phenylenediamine (MPD) and trimesoyl chloride (TMC) reactants or piperazine (PIP) and TMC reactants. The elastic modulus of the films was determined using atomic force microscopy (AFM). The results show that the modulus was independent of film thickness with values of 4.36 ± 1.19 GPa and 5.24 ± 1.06 GPa for the MLD films grown using the MPD-TMC and PIP-TMC chemistries, respectively. These values are of the same order of magnitude as those reported for much thicker polyamide films, but higher than the modulus of polyamide films fabricated using interfacial polymerization.