By exactly locating pendant PEG550 segments at varying intervals along a hydrocarbon-rich polyester backbone, the lamellar dimension has been precisely tuned.

The mutual immiscibility between the three segments, namely backbone HC, and pendant PEG and FC segments, causes zigzag folding of the polymer such that FC segments lie on one side and PEG on the other, thereby generating Janus-type folded chains.

Periodically grafted amphiphilic copolymers (PGACs) were earlier shown by us to adopt a zigzag folded conformation in the solid state, which enabled the backbone and pendant segments to segregate and occupy alternate layers in a lamellar structure. The conformational transition from a random coil to a zigzag folded chain in solution is an interesting problem, which is largely unexplored. To examine this, an orthogonally clickable parent polyester was sequentially clicked with two types of poly­(ethylene glycol) (PEG) segments: one is a simple PEG and the other is a PEG that carries a dipolar chromophore. These two hydrophilic PEG segments, installed in a periodic and alternating fashion along the hydrocarbon-rich (HC) polyester backbone, ensure that the Janus folded chains are formed upon folding and carry chromophoric dipoles oriented along the same direction, thereby generating a large net dipole. The folding-induced alignment of chromophores in solution was followed using second harmonic light scattering (SHLS), wherein the intensity of the frequency-doubled scattered light (I 2ω) is measured. Folding was induced by adding a polar solvent, like methanol, to a chloroform solution of the polymer; methanol desolvates the HC backbone but solubilizes the pendant PEG segments, thus inducing folding. The second harmonic intensity (I 2ω) increased initially with methanol concentration and then saturated; in contrast, I 2ω remained invariant with the solvent composition in the case of an analogous model chromophore. Furthermore, in a model PGAC carrying chromophore-bearing PEG segments on every repeat unit, I 2ω decreased with increasing methanol composition, revealing the formation of a centrosymmetric folded chain, wherein the chromophoric dipoles on either side cancel each other. Thus, this study clearly reveals that the zigzag chain folding of PGACs can be induced by a segment-selective solvent, resulting in the rather elusive directional ordering of chromophoric dipoles in solution.

Dynamic covalent networks (DCNs) use chemical bonds that break and reform at appropriate processing conditions to allow reconfiguration of the networks. Recently, the acylsemicarbazide (ASC) motif has been added to the repertoire of such dynamic covalent bonds, which is capable of hydrogen bonding as well as dynamic bond exchange. In this study, we show that its sulfur congener, thioacylsemicarbazide (TASC), also acts as a dynamic covalent bond, but exchanges at a slower rate than the ASC moiety. In addition, siloxane‐based DCNs comprising either ASC or TASC motifs or a varying composition of both show tunable relaxation dynamics, which slow down with an increasing amount of TASC motifs. The reduction in stress relaxation goes hand in hand with a reduction of creep in the network and can be tuned by the ASC/TASC ratio. All networks are readily processed using compression molding and dissolve when treated with excess hydrazide in solution. The ability to control network properties and creep in dynamic covalent polymeric networks by small changes in the molecular structure of the dynamic bond allows a generalized synthetic approach while accommodating a wide temperature window for application.