Visualization of the Formation of Interfacially Polymerized Film by an Optical Contact Angle Measuring Device

Abstract

Interfacial polymerization (IP) is widely used in the synthesis of thin film composite membranes and encapsulation of active ingredients. However, there are few reports on the observation of film formation by IP. In the present work, a visualized technology was developed for studying film formation by interfacial polymerization. An optical contact angle measuring device (OCA) was used to visualize the morphology of pendant drop of aqueous solution immersed in organic solution and the film formed during interfacial polymerization process. First, the variations of the morphology of pendant drop of aqueous solution were studied, the results offered in situ experimental evidence for the growth of interfacial film toward the organic phase. Furthermore, the effects of various synthesis conditions on film morphology were studied. It was found that the bubbles were generally appeared on the films. The bubbles on the films were attributed to the instability arising from the formation of the nascent solid thin film with a huge surface energy per volume. The bubbles on the films could ultimately result in the rough membrane surface. This paper also indicated that OCA is a very useful tool for in situ studying the fundamentals of IP film formation process.

3D visualization of the internal nanostructure of polyamide thin films in RO membranes

“…This is consistent with the postulate that MPD-TMC polyamide thin films grow towards the organic phase [4,9]. The formation of bubble-like voids with equivalent asymmetric size distributions has been documented for other IP processes producing polyamide [44] and polyester [45] films that are, however, orders of magnitude thicker than MPD-TMC thin films. Nonetheless, the film characterized in [44] showed properties typical of polyamide films such as a relatively smoother surface on the aqueous side.…”

Improved performance of polyamide thin-film composite nanofiltration membrane by using polyetersulfone/polyaniline membrane as the substrate

“…It is well known that the fabrication of a PA layer involves a reaction between the PIP monomer in the aqueous solution that the substrate is soaked in, with the TMC monomer in the organic solution that covers the top surface of the substrate [46][47][48]. During this process, the rate-limiting step is the diffusion of PIP monomer through the aqueous solution from the pores of substrate to the interface.…”

“…During this process, the rate-limiting step is the diffusion of PIP monomer through the aqueous solution from the pores of substrate to the interface. The faster the PIP is supplied, the more severe the interfacial reaction and the greater the degree of polymer cross-linking [22,46,47]. Obviously, the surface properties of substrates play an important role in the diffusion of the PIP monomer during interfacial polymerization process.…”

Study on the thin film composite poly(piperazine-amide) nanofiltration membrane: Impacts of physicochemical properties of substrate on interfacial polymerization formation

“…The faster the PIP supply, the more is the chance of cross-linking formation and, conversely, the slower the PIP supply there is more chance of linear polymer formation. Moreover, the formed barrier layer would continually grow toward the organic phase and the growth rate of the poly(piperazine-amide) layer, subsequently, would be limited by diffusion of PIP through the newly-formed poly(piperazineamide) layer [2,30,32,33].…”