Tacticity Effects on the Local Conformation and Interfacial Properties of poly (methyl methacrylate) at the Liquid-Vapor Interface

The orientation of functional groups of poly (methyl methacrylate) (PMMA) play a key role in understanding functionalities like wettability, aggregation and solvent interaction. We have studied the orientation of different functional groups such as the $\alpha $-methyl, ester methyl, methylene and carbonyl groups of the PMMA chain through all atom Molecular Dynamics (MD) simulations for different chain lengths of the polymer. Through orientational correlation, and number density computations we are able to establish the identity and extent of groups coming to the surface. Surface tensions are computed to validate our PMMA model. Analysis has been carried out for all three tacticities-atactic, syndiotactic, and isotactic. Sum Frequency Generation (SFG) spectroscopy also provides insight into the orientation of various groups at the liquidvapor interface. Characterization of the SFG peaks is the point of some debate and MD simulations aim to aid in the understanding of local ordering.