Faculty Advisor

Peterson, Amy M.


Polyelectrolyte multilayers (PEMs), thin polymer films assembled from polyelectrolytes, are used to coat bulk materials to modify surface properties, making the optimization of these properties critical. This study examined the influence of polyelectrolyte molecular weight (MW) and the resulting assembly pattern by creating PEMs with poly(acrylic acid) (PAA) and poly-l-lysine (PLL) at low, medium, and high MW to determine their effects on the surface free energy (SFE) and roughness. Mass increased with MW, as did the ratio of PAA:PLL. Medium MW PEMs were the smoothest, and had the lowest SFE; low MW PEMs were the roughest and had the highest SFE. High MW PEMs were rough while having low SFE. These results demonstrate the tunability of surface properties including SFE and roughness with MW.


Worcester Polytechnic Institute

Date Accepted

March 2018


Chemical Engineering

Project Type

Major Qualifying Project



Advisor Department

Chemical Engineering