Polymers are used industrially to alter surface properties such as anti-fouling, lubrication, adhesion or wettability. The key factor in all these processes is adsorption of the polymer to the surface. We investigated how changes in molecular architecture impact the adsorption processes. Nanoscale analysis with quartz crystal microbalance (QCM) and atomic force microscopy (AFM) allow for evaluation of the amount of polymer adsorbed in real-time and the wet coat thickness between the coated surface and borosilicate glass respectively. In the present study we investigated the surface adsorption kinetics of PEO-PDMAEMA as a function of the molar ratio between the two blocks (5:2.5, 5:5.6, and 5:12.0), whose maximum adsorption amounts are 60, 110, and 150 ng/cm<sup>2</sup>, respectively. The difference in adsorption is likely because the PDMAEMA blocks act as the surface anchoring points, driven by the electrostatic attraction with the negatively charged silicon surface. As concentration increases, the amount of mass adsorbed increases linearly for 5:5.6. The 5:2.5 has a smaller PDMAEMA anchoring segment, resulting in less adsorption of polymer onto the surface. No increase in mass adsorbed is observed for the 5:12 above 150 ppm concentration, suggesting the polymer has fully saturated the surface as shown in Figure 1a. Maximum adsorption occurs due to the large PDMAEMA anchoring segment of the block co-polymer onto the surface. AFM measurements show that the block co-polymer 5:2.5 has the largest wet thickness of around 65 nm and 5:12 has the smallest wet thickness of around 40 nm, as shown in Figure 1b. Whilst 5:2.5 has the smallest anchoring segment, it has the largest PEO group which won’t be bound to the surface but faces the bulk solution, indicating that the PDMAEMA is the binding factor involved in surface deposition. QCM and AFM collectively allow us to determine molecular properties that affect surface deposition.

Effect of block co-polymer architecture on its surface deposition

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.