Block copolymers (BCPs) with a high Flory−Huggins interaction parameter (χ) are promising alternatives to conventional nanopatterning materials for future nanolithography and nanotechnology applications. Herein, we described AB-and ABA-type BCPs comprising oligosaccharides (maltoheptaose, maltotriose, and maltose as the A block) and poly(propylene oxide) (PPO, as the B block) as new high-χ BCP systems, which can be termed "Sweet Pluronics". The BCPs were successfully synthesized by click reaction between azidofunctionalized PPO and propargyl-functionalized maltooligosaccharides. These BCPs undergo microphase separation in bulk state to provide various nanopatterns, i.e., sub-4 nm nanofeatures (cylinders, lamellae, and spheres) with domain spacing as low as 6.2 nm, depending on their composition and the applied annealing conditions. The thin film of these BCPs fabricated on a silicon substrate also showed various microphase-separated structures. When the BCP thin films were subjected to high-temperature solvent vapor annealing using a µ-wave oven as the heating source, their morphologies changed from parallel lamellar to cylindrical because of the preferential swelling of PPO. Overall, these results confirmed that the present "Sweet Pluronics" system is promising high-χ materials for sub-4 nm nanopatterning applications.

Herein, we compared the microphase-separation behavior and mechanical properties of cellulose- and amylose-based block copolymers (BCPs). Various cellooligosaccharide triacetate-b-poly­(δ-decanolactone)-b-cellooligosaccharide triacetates (AcCel n -b-PDL-b-AcCel n s), which are cellulose-based ABA-type BCPs, with PDL molecular weights of approximately 5, 10, and 20 kg mol–1 and PDL volume fractions of 0.65, 0.77, and 0.87, were synthesized from α,ω-diazido-end-functionalized PDLs and propargyl-end-functionalized cellooligosaccharide triacetates via click chemistry. We adopted the cellodextrin-phosphorylase-mediated oligomerization of α-d-glucose-1-phosphase in the presence of a propargyl-end-functionalized cellobiose primer to synthesize the functional cellooligosaccharide segment. The maltooligosaccharide triacetate-b-poly­(δ-decanolactone)-b-maltooligosaccharide triacetate (AcMal n -b-PDL-b-AcMal n s) amylose counterparts were also synthesized in a similar manner. Small-angle X-ray scattering experiments and atomic force microscopy revealed that AcCel n -b-PDL-b-AcCel n s are more likely to microphase-separate into ordered nanostructures compared to AcMal n -b-PDL-b-AcMal n s, despite their comparable chemical compositions and molecular weights. Furthermore, AcCel n -b-PDL-b-AcCel n s exhibited significantly superior mechanical performance compared to their amylose counterparts under tensile testing, with Young’s modulus and stress at break of AcCel n -b-PDL10k-b-AcCel n being 2.3 and 1.8 times higher, respectively, than those of AcMal n -b-PDL10k-b-AcMal n . The enhanced microphase-separation and mechanical properties of AcCel n -b-PDL-b-AcCel n s were found to be attributable to the stiffness and crystalline nature of the AcCel n segments. These results demonstrate the advantages of using cellulose derivatives to synthesize novel biofunctional materials.