Self-Assembly of Repetitive Segment and Random Segment Polymer Architectures

Abstract

Recent advances in chemical synthesis have created new methodologies for synthesizing sequence-controlled synthetic polymers, but rational design of monomer sequence for desired properties remains challenging. In this work, we synthesize periodic polymers with repetitive segments using a sequence-controlled ring-opening metathesis polymerization (ROMP) method, which draws inspiration from proteins containing repetitive sequence motifs. The repetitive segment architecture is shown to dramatically affect the self-assembly behavior of these materials. Our results show that polymers with identical repetitive sequences assemble into uniform spherical nanoparticles after thermal annealing, whereas copolymers with random placement of segments with different sequences exhibit disordered assemblies without a well-defined morphology. Overall, these results bring a new understanding to the role of periodic repetitive sequences in polymer assembly.

An Undergraduate Laboratory Module Integrating Organic Chemistry and Polymer Science

“…Students determined the average hydrodynamic dimeter of these spherical structures by ImageJ analysis and reported the diameter in the range of 30–60 nm (average aggregate size = 38.6 nm and standard deviation = 9.5 nm (total sample size = 40). This result was a demonstration to the students that sequence and length-controlled synthetic peptide repeat unit forms well-defined nanoscale morphology, like the repeat sequences regularly found in natural proteins. ,, Lastly, students performed thermal analysis of these two synthesized polymers, as shown in Figure . TGA measurement for PA sample (Figure a) showed 10 wt % decomposition ( T d,10% ) at 225 °C, which reflects the degradation-induced mass loss.…”

“…This result was a demonstration to the students that sequence and length-controlled synthetic peptide repeat unit forms well-defined nanoscale morphology, like the repeat sequences regularly found in natural proteins. 1 , 21 , 39 Lastly, students performed thermal analysis of these two synthesized polymers, as shown in Figure 4 . TGA measurement for PA sample ( Figure 4 a) showed 10 wt % decomposition ( T d,10% ) at 225 °C, which reflects the degradation-induced mass loss.…”

Modulating Polymerization Behaviors of Ether–Ester Monomers and Physicochemical Properties of Poly(ether-alt-ester)s by Heteroatom Substitutions

“…Alternating copolymers have attracted widespread attention in both academia and industry, thanks to their unique properties compared to random copolymers. , Placing the monomer in a strictly alternating sequence provides access to valuable materials with desired properties. Among numerous alternating polyesters, poly­(ether- alt -ester)­s combine both the flexibility of ether linkages and the degradability of ester moieties and thus exhibit improved performance.…”

Concurrent Reduction and Stabilization of Graphene Oxide Dispersion by Silk-Inspired Polymer

“…Moreover, XRD supports the successful occurrence of DA, demonstrating the complete disappearance of the furan crystalline peaks in polymer 4 (Figure S7). Next, we conducted TEM/cryo-TEM; we found that sequence-controlled silk-inspired polymer 4 self-assembles into spherical micellelike nanostructures , in aqueous solution with an average diameter of 49.1 ± 10.4 nm (Figure c,d). However, the drop-cast sample exhibited fiberlike structures (Figure e) with an average width of 9.1 ± 1.3 nm.…”