eprintid: 9538 rev_number: 6 userid: 6 dir: disk0/00/00/95/38 datestamp: 2011-11-10 20:03:44 lastmod: 2016-11-15 13:51:01 status_changed: 2011-11-10 20:03:44 type: thesis_degree metadata_visibility: show contact_email: j1e1c1@yahoo.com item_issues_count: 0 eprint_status: archive creators_name: Copenhafer, James Edward creators_email: j1e1c1@yahoo.com title: Synthesis and Characterization of Poly(9,9-Dihexylfluorene-mb-methylene)s ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: OLED; polymer abstract: The synthesis and characterization of copolymers possessing exact repeating sequences of 9,9-dihexylfluorene and methylene repeat units are described. Each poly(9,9-dihexylfluorene-mb-methylene) (PFM, mb = multiblock) was synthesized following the assembly of a symmetrically disubstituted monodisperse oligofluorene. Alkyl segments possessing terminal alkene functionality were then coupled at both of the substituted positions on the oligofluorene to give a macromolecular "segmer" compound. Each segmer was polymerized using Acyclic Diene Metathesis (ADMET) and, following post-polymerization hydrogenation, a PFM with an entirely repeating diblock sequence was produced. PFMs possessing 9,9-dihexylfluorene segment lengths of x = 1, 2, 3, 4, 7, or 8 units and methylene segment lengths of y = 10 or 18 units were prepared to give a ten member PFM library. As PFMs have exact chemical compositions and monomer unit sequencing, studies aimed at elucidating solution and bulk phase trends were performed. Spectroscopic characteristics that make polyfluorene-type materials attractive include their generally efficient blue light emission (λmax ~ 448 nm). Successful investigations into the optical tuning of PFMs in solution and in the bulk are described. Additionally, thermal- and photostabilities of PFMs under a variety of conditions are reported and compared to the related homopolymer, poly(9,9-dihexylfluorene) [PDHF]. Compared to PDHF, PFMs display similar, and in some cases superior resistance to photobleaching processes. Additionally, thermal and photostability investigations into keto-induced degradation processes of PFMs suggest that interruption of the fluorene segments with alkyl spacers effectively suppresses intrachain charge migration and interchain Förster energy transfer in the bulk. The rate of PFM, and likewise PDHF degradation was found to be at least partially dependent on the initial state of the sample.Efforts toward the transition metal-catalyzed production of cyclic oligomers are described. Two rigid bifunctional molecules bearing both transition-metal metathesis initiating and terminating groups were prepared. The synthesis and metathesis activity of these compounds are reported. date: 2007-01-29 date_type: completed institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Meyer, Tara etdcommittee_name: Beckman, Eric etdcommittee_name: Petoud, Stephane etdcommittee_name: Chapman, Toby etdcommittee_email: tmeyer@pitt.edu etdcommittee_email: beckman@engr.pitt.edu etdcommittee_email: spetoud@pitt.edu etdcommittee_email: tchapman@pitt.edu etdcommittee_id: TMEYER etdcommittee_id: BECKMAN etdcommittee_id: SPETOUD etdcommittee_id: TCHAPMAN etd_defense_date: 2006-11-06 etd_approval_date: 2007-01-29 etd_submission_date: 2006-10-29 etd_access_restriction: 5_year etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.9538 thesis_type: dissertation degree: PhD committee: Tara Meyer (tmeyer@pitt.edu) - Committee Chair committee: Eric Beckman (beckman@engr.pitt.edu) - Committee Member committee: Stephane Petoud (spetoud@pitt.edu) - Committee Member committee: Toby Chapman (tchapman@pitt.edu) - Committee Member etdurn: etd-10292006-104853 other_id: http://etd.library.pitt.edu/ETD/available/etd-10292006-104853/ other_id: etd-10292006-104853 citation: Copenhafer, James Edward (2007) Synthesis and Characterization of Poly(9,9-Dihexylfluorene-mb-methylene)s. Doctoral Dissertation, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/9538/1/Copenhafer_Thesis_2006.pdf