Block-copolymers (BCPs) represent a class of functional materials with properties that can be readily tuned by modifying the chemical identity and compatibility between the different blocks. This, in turn, strongly affects their structural organization and phase-separation. BCPs with immiscible segments create nanoscopic patterns on solid surfaces with domains sizes proportional to the length of each block. Such self-assembled periodic structures are promising for soft nanolithography, but are limited to domain sizes significantly larger than 10 nm. Sub-10 nm domain sizes may be better achieved with so-called high χ-low N structures and block molecules. While the bulk organization of such systems can be studied at sub-10 nm resolution with X-Ray Scattering techniques, the single molecule characterization of the nanophase separation between their incompatible blocks has not been carried out to date.<br/>Here we present a novel, rationally designed block molecules composed of highly immiscible blocks composed of naphthalenediimides (NDIs) and oligodimethylsiloxanes (ODMS). The adsorption, nanophase separation and influence of ODMS on the surface-directed self-assembly were studied on graphite surface using scanning probe microscopy (STM and AFM). A comparison between our results and previous studies on oligomethylene functionalized-NDI provides new insights into the interplay of supramolecular interactions between the different blocks and the surface. The understanding of the nanophase separation at the single molecule level will provide a valuable feedback for tuning the morphology and periodicity via manipulation of the block architecture, which will ultimately extend the applicability of block molecules lithography.

Nano-phase behavior of surface-adsorbed, monodisperse oligodimethylsiloxane-based block molecules

253rd National Meeting (2017)

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