Dynamic Sub-10-nm Nanostructured Ultrathin Films of Sugar Polyolefin Conjugates Thermoresponsive at Physiological Temperatures

Spin-casting of a cellobiose-atactic poly propene (CB-aPP) conjugate (1) from a 0.1% (w/w) n-butanol/hexane solution onto highly oriented pyrolytic graphite (HOPG) and carbon-coated Si(100) spontaneously produced microphase-separated sub-10-nm nano structured ultrathin films in the form of alternating CB and aPP lamellar domains (d = 6.60 +/- 0.68 nm) that are oriented perpendicular to the substrate surface. Thermal annealing at modest temperatures (e.g., 50-100 degrees C), and as low as the physiologically relevant temperature of 38 degrees C, serves to drive a structural transition that yields a parallel stacked bilayer assembly as the thermodynamically favored nanostructure. These results establish the advantage of low molecular weight, narrow polydispersity, and amorphous, low T-g, poly(alpha-olefinate)s (xPAOs) as a new class of hydrophobic building block for amphiphilic materials, and sugar PAO conjugates in particular, for the development of stimuli-responsive, nanostructured materials for technological applications at physiological temperatures.