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Published in Joseph C. Salamone, Polymeric Materials Encyclopedia, 2020
Poly(p-phenylene vinylene) (PPV) and related polymers have emerged as the most widely studied n-conjugated polymer class, mainly because they show many interesting and potentially useful opto- and photoelectronic properties. The sulfonium precursor route to PPV is particularly well known and involves the polymerization of p-xylene bis-(tetrahydrothiophenium chloride), or of its analogs or derivatives, in the presence of a base in water or methanol to give the corresponding sulfonium precursor polymer. The Heck reaction, which involves a palladium-catalyzed coupling reaction between an aryl halide and a vinyl compound, has been shown to be a useful approach for the preparation of PPV derivatives and phenylene vinylene oligomers. The sulfonium precursor route synthesis has enabled unique processing flexibility to achieve uniaxially or biaxially oriented PPV thin films. The dark electrical conductivity of pristine PPVs was investigated in the 1970s for the samples prepared by the Wittig reaction.
Light-Emitting Polymers
Published in Zhigang Rick Li, Organic Light-Emitting Materials and Devices, 2017
Shidi Xun, Dmitrii F. Perepichka, Igor F. Perepichka, Hong Meng, Fred Wudl
Poly(p-phenylene vinylene) (PPV) 1 is a highly stable conjugated polymer (Chart 2.1). Its yellow color is due to an absorption band centered at ~400–420 nm (depending on the method of synthesis) with an onset corresponding to a band gap of ~2.5 eV [5]. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels in PPV can be accessed through cyclic voltammetry (CV) experiments that, under proper conditions, reveal chemically reversible oxidation and reduction waves (Figure 2.1). The deduced electrochemical gap corresponds reasonably well to the optical band gap. As a relatively good electron donor, PPV and its derivatives can be chemically doped by strong oxidizing agents and strong acids, affording highly conductive p-doped materials (with conductivity up to ~104 S/cm [5]). The yellow–green fluorescence of PPV 1 results from a vibronically structured emission band with peak maxima at 520 and 551 nm (Figure 2.1).
A review on the recent progress, opportunities, and challenges of 4D printing and bioprinting in regenerative medicine
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Parvin Pourmasoumi, Armaghan Moghaddam, Saba Nemati Mahand, Fatemeh Heidari, Zahra Salehi Moghaddam, Mohammad Arjmand, Ines Kühnert, Benjamin Kruppke, Hans-Peter Wiesmann, Hossein Ali Khonakdar
In a recent study, Wang et al. [83] fabricated aligned myofibers construct and controllable curvature for cardiac tissue engineering. Digital light processing printing was the fabrication method, and constructs under near-infra-red radiation changed their shape to mimic natural tissue's complex and curved morphology. Shape memory polymer and graphene provided this property, and cell culture studies proved the capability of the 4 D printed structure. The results showed a uniform aligned distribution and maturation of myocardial cells.Poly (p-phenylene vinylene–co–p-pyridylene vinylene) derivatives