Probing of the Reaction Progress at a PMMA/PS Interface by Using Anthracene-Labeled Reactive PS Chains

Abstract

The progress of the interfacial reaction of polystyrene chains end-capped by a primary amine (PS-NH2) and PMMA chains end-capped by an anhydride (PMMA-anh) has been monitored by SEC-UV, by using anthracene-labeled polystyrene chains (anth-PS-NH 2) as a probe. Assemblies of an anth-PS-NH2 layer and a PMMA-anh layer were annealed at 200 °C for various periods of time. The interfacial reaction rate depends on the molecular weight (MW) of the reactive precursors in relation to the χN value of the chains. For chains of low χN (χN ) 6), the reaction is faster because the interface becomes more diffuse with time, as observed by TEM and AFM, consistent with compatibilization of the weakly immiscible polymers by the copolymer formed in-situ. For chains of higher molecular weight and χN (10, instead of 6), the interface is much sharper and the residence time at the interface of the symmetric diblock copolymer of higher molecular weight is also increased, which dramatically restricts the progress of the interfacial reaction under the annealing conditions used in this work.

Understanding the Grafting of Telechelic Polymers on a Solid Substrate to Form Loops

“…Therefore, the interfacial reaction is not solely determined by the diffusion of the functionalized polymer to the reactive interface. The reaction limited nature of similar interfacial reactions 27,28,31,57,60,61,65,66 has also been observed.…”

“…As mentioned above, most studies on the interfacial reaction at a polymer/ substrate or polymer/polymer interface were found to be reaction-controlled. 27,28,31,57,59,61,65,66 However, diffusion-controlled processes have been observed. For example, Harton et al 67 studied an interfacial reaction for a highly reactive complementary polymer pair at a low annealing temperature.…”

Polymer Blend Compatibilization by Copolymers and Functional Polymers

“…This effect cannot be associated with the diffusion of the low molecular weight chains, since several studies evidenced that the interfacial reaction is controlled by the collision efficiency of the reactive groups and not by diffusion. Instead, Yin [55] proposed that the dependence of the reactivity on the molecular weight could be related to the interfacial thickness, as shown by Helfand and Tagami [73] and Broseta [74]. As described before, the reaction rate at the interface usually decreases dramatically as the critical concentration of interfacial copolymers is formed.…”

“…Various studies relating to the morphology of static reactive interfaces demonstrated that these can become highly irregular after the reaction between the reactive precursors [55][56][57][58]. A few researchers [59][60][61][62][63] measured the interfaces irregularity as a function of the reaction time and compared them with the S values determined experimentally.…”

“…Several studies demonstrated that the reaction rate at the interface depends on the reactive precursor molecular weight (functional polymer), being higher for lower molecular weights [55,71,72]. This effect cannot be associated with the diffusion of the low molecular weight chains, since several studies evidenced that the interfacial reaction is controlled by the collision efficiency of the reactive groups and not by diffusion.…”