Aissou K, Otsuka I, Rochas C, Fort S, Halila S, Borsali R. Nano-organization of amylose-b-polystyrene block copolymer films doped with bipyridine.
LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011;
27:4098-4103. [PMID:
21395269 DOI:
10.1021/la104936k]
[Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper discusses the self-assembly of rod-coil amylose-b-polystyrene (Mal-b-PS) block copolymer thick and thin films. The nano-organization falls in an interdomain spacing d of about 10 nm, much smaller than flexible-flexible petrol block copolymer systems. Additionally, hydrogen-bonding interactions between carbohydrate rods (amylose) and 4',4-bipyridine (bipy) molecules induces phase transitions. Indeed, adding bipy in maltooctadecaose-block-polystyrene (Mal18-b-PS) copolymers results, at room temperature, in the formation of a lamellar phase having Mal18 bipy-rich nanodomains instead of hexagonal close-packed (HCP) of cylinders made of Mal18, whereas a coexistence of Mal7bipy-rich cylindrical and spherical nanodomains are formed from maltoheptaose-b-polystyrene (Mal7-b-PS) copolymers instead of a poorly organized array of Mal7-based cylinders. On heating, the Mal7bipy-b-PS system shows more rich phase behavior as compared to the Mal7-b-PS one due to weakening of hydrogen bonding with temperature. Such a system is of great interest in developing active layers in light-emitting diodes (LEDs) or in photovoltaic cells to realize devices with an optimal structure, that is, having large interface area and domain size with similar exciton diffusion length (10 nm).
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