Molecular Design\nof a Discrete Oligosaccharide-<i>block</i>-Oligodimethylsiloxane\nSystem: Toward Microphase Separation\nwith 1 nm Domain Size and Angstrom-Scale Size Control

Herein, we present a novel discrete block copolymer (BCP)\nsystem\nconsisting of oligodimethylsiloxane and maltooligosaccharide in which\nthe polymerization degrees of both blocks can be modulated at one-monomer\nresolution, allowing synthetic access to a discrete BCP with degree\nseries of polymerization. The thiol–ene reaction of α,ω-diallyl-functionalized\noligodimethylsiloxanes with thiol-functionalized maltooligosaccharides\nreadily accessed the discrete BCPs. Small-angle X-ray scattering revealed\nmicrophase-separated lamellar structures with <i>d</i> of\n3.59–4.99 nm depending on the degree of polymerization, among\nthe smallest ever reported in sugar-based BCPs. Moreover, the <i>d</i>-value was precisely controlled on the scales of 0.4–0.5\nÅ and 0.59–0.85 nm by increasing or decreasing the monomeric\nglucose and dimethylsiloxane units, respectively. In addition, we\ndiscovered that the degree of polymerization, linker structure, and\nmolecular weight distribution significantly impact the dimensions\nand structural stability of the BCPs.