Effect of Confinement on the Synthesis of PMMA in AAO Templates and Modeling of Free Radical Polymerization

Abstract

The hierarchical surface structure of polymer materials leads to unique properties which are of both academic and commercial interest. In this work we explore the ability to replicate the well-defined surface structure of anodic aluminum oxide (AAO) templates by in situ polymerization of methyl methacrylate. When the reaction is conducted inside the templates, the rate of polymerization was significantly higher and molecular weight was reduced, as compared to the reaction in bulk. These observations were explained using a mathematical model to describe the polymerization based on free-volume theory and confinement effects. As the dimensions of the template are reduced, a catalytic effect on the rate of initiator decomposition leads to a faster polymerization rate in the early stages of polymerization. In addition, due to the confined reaction volume, the rate of termination is increased in the latter stages of the reaction. The two confinement effects combine to lead to lower molecular weight polymers of reduced dispersity in comparison to the reaction conducted in bulk.

A Patterned Butyl Methacrylate-co-2-Hydroxyethyl Acrylate Copolymer with Softening Surface and Swelling Capacity

“…An alternative method to design polymer nanostructures is the in-situ polymerization of a polymer precursor monomer into AAO nanocavities. So far, the advantage of polymer nanofabrication within AAO nanocavities has been demonstrated as a straightforward pattern of polymer nanostructures in the case of the in-situ free radical polymerization of styrene [ 7 ], methyl methacrylate [ 8 ], or fluoracrylic monomers [ 9 ]. In all cases, high reaction conversion with controllable molecular weight and molecular weight dispersities, in comparison to bulk polymerization in the same conditions, was reached in a few hours.…”

Effects of Polymer Confinement in AAO Nanocavities on the Microstructure and Properties of Polymer Materials

“…In particular, the radical polymerization of vinyl monomers, such as, methyl methacrylate (MMA), styrene (St), and perfluoracrylate (FA) and the step-growth polymerization of a diol and a diisocyanate has been successfully achieved in the pores of AAO templates. [35][36][37][38][39] Another illustrative example of polymerization in confinement has been reported by Tarnacka et al upon step-growth polymerization of bisphenol-A diglycidyl ether (DGEBA) with aniline both in bulk and in AAO membranes. 40 In this case, the kinetic of reaction was followed by both FTIR and Broadband Dielectric Spectroscopies.…”

Polymerization Kinetics of Cyanate Ester Confined to Hydrophilic Nanopores of Silica Colloidal Crystals with Different Surface-Grafted Groups

“…Confined polymerization attracts research attention as a means of controlling the properties of polymers, such as molecular weight distribution [ 11 , 12 , 13 ], crystallinity [ 14 , 15 , 16 ], tacticity [ 13 , 17 , 18 ], and glass transition temperature [ 19 , 20 , 21 ]. Currently, the most studied type of confined polymerization is radical polymerization.…”

“…Currently, the most studied type of confined polymerization is radical polymerization. For this type of polymerization the changes in the reactivity of monomers have been explained as the effects of confinement on the rates of the initiation [ 11 ] and termination [ 17 , 22 ]. Polycyclotrimerization of cyanate esters is another type of reaction for which the effect of confinement on both reactivity of the reactant monomer and product polymer has been well documented [ 23 , 24 , 25 , 26 , 27 , 28 ].…”