Patterned Layers of a Semiconducting Polymer via Imprinting and Microwave‐Assisted Grafting

Abstract

Enhancements in both the rate and extent of grafting of poly(9,9'-n-dihexyl fluorene) (PDHF) onto flat and nanopatterned crosslinked photopolymer films are described. Reactivity of the surfaces toward grafting via the Yamamoto-type Ni(0)-mediated coupling reaction is increased by synthesizing and incorporating 2,7-dibromo-9-fluorenyl methacrylate (DBFM, 2) as a new grafting agent. Varying the concentration of surface-embedded DBFM is shown to control both overall graft formation and fluorescence with a maximum thickness of up to 30 nm and peak emission at 407 nm for 40 wt% loading. In addition, microwave irradiation is introduced as an effective means to drive graft formation and thus allows fabrication of PDHF-functionalized surfaces in as little as 30 min. Both forms of improvement are extended to DBFM-embedded, nanocontact-molded features ranging in size from 100 microm to 100 nm in width and 60 nm in height. Microwave-assisted grafting from these patterned surfaces produces fluorescent features as imaged by optical microscopy and a corresponding increase in feature height as measured by atomic force microscopy.

Kumada Catalyst‐Transfer Polycondensation: Mechanism, Opportunities, and Challenges

“…Yamamoto step-growth polycondensation, [106,107] only thin grafted layers can be formed under harsh reaction conditions, and a predominant quantity of ungrafted polymer forms as well. The surface-initiated polymerization (SIP, or ''grafting-from'') technique usually results in significantly thicker films and can be easily applied to fabricate patterned substrates.…”

Versatile functional poly(3‐hexylthiophene) for hybrid particles synthesis by the grafting onto technique: Core@shell ZnO nanorods

“…The surface grafting of conjugated polymer is a recent field that started in 2004 when Emrick et al showed that CdSe nanocrystals could be integrated into PPV thin films without aggregation . Several techniques have been used via the “grafting through” method to create conjugated brushes, such as Yamamoto, Sonogashira, or Suzuki coupling polycondensations. “Grafting from” has also been developed to graft P3HT via surface‐initiated Kumada catalyst transfer polycondensation.…”

Microwave-assisted one-pot synthesis of water-soluble rare-earth doped fluoride luminescent nanoparticles with tunable colors

“…It has been employed to exploit new materials. As a new heating source, microwave irradiation has been successfully used in a number of chemical approaches to produce many types of nanoparticles, such as metal [23], II–VI group semiconductors [24], oxides [25], vanadium metal-organic frameworks [26], fluoride [27], phosphates [28,29], and even for the grafting of poly(9,90-n-dihexylfluorene) (PDHF) onto flat and nanopatterned crosslinked photopolymer [30]. …”