Microphase separation of a quadruple hydrogen bonding supramolecular polymer: effect of the steric hindrance of the ureido-pyrimidone on their viscoelasticity

Abstract

The supramolecular polymers based on 2-ureido-4[1H]-pyrimidone (UPy) with different structure were prepared and the effects of microtopography on the viscoelasticity were investigated.

A Critical Approach to Polymer Dynamics in Supramolecular Polymers

“…It has been in particular shown that even in high molecular weight polymer matrix (low UPy concentration) the phase separation exists and it contributes to stress relaxation mechanism, so the polymer chains do not behave like linear chains the Cates model hypothesized (Figure ). , Therefore, a plethora of studies reported the contribution of UPy stacking on polymer dynamics as an inevitable part of this sticker. , This is indeed a big disadvantage when comparing with theories, although in some studies this effect has not been truly addressed. , For instance, in one study by Binder et al on PnBA end-capped with THY and/or DAT the absence of a plateau in the frequency sweeps was related to the absence of phase separation . However, the corresponding slopes in the terminal regime did not show Maxwell behavior, similar to many studies where phase segregation was present and led to smaller terminal slopes instead of plateau formation .…”

“…96,34 Therefore, a plethora of studies reported the contribution of UPy stacking on polymer dynamics as an inevitable part of this sticker. 97,98 This is indeed a big disadvantage when comparing with theories, although in some studies this effect has not been truly addressed. 99,100 For instance, in one study by Binder et al on PnBA end-capped with THY and/or DAT the absence of a plateau in the frequency sweeps was related to the absence of phase separation.…”

Critical Role of the Interfacial Layer in Associating Polymers with Microphase Separation

“…Such phase separation has been found in different kinds of associating polymers, for example, in ionomers , or polymers with hydrogen bonding and even in some vitrimers . The clusters of functional groups can form a solid phase in the polymer melt , if their glass-transition temperature ( T g ) or melting temperature T m is higher than T g of the polymer backbone. The characteristic structure and morphology of these clusters can also be tuned with the architecture of the polymers .…”

Emergence, evidence, and effect of junction clustering in supramolecular polymer materials

“…In a similar system with a PBd core, nanofiber assemblies gradually disappear by increasing the size of the substituent on the sixth position from a methyl to a n-octyl. 101 Along the same lines, a low-frequency plateau emerges in unentangled side-chain UPy grafted poly(lauryl methacrylate) (PLMA) systems due to the aggregation of UPy dimers, which diminishes upon introduction of the bulky adamantyl group in the sixth position. 56 Surprisingly, this modification works oppositely in entangled systems.…”