Deep‐Blue Fluorescent Particles via Microwave Heating of Polyacrylonitrile Dispersions

Abstract

This study presents a new method to produce fluorescent particles. Established methods are based on the incorporation of conjugated dye molecules into dielectric polymer matrices or preparation of colloids, which are composed of fluorescent conjugated polymer. By contrast, this study presents a method where dielectric polyacrylonitrile is exposed to microwave radiation leading to an intramolecular cyclization reaction producing π-conjugated segments, which fluoresce blue. During this conversion, the particles shrink in diameter but as an ensemble they retain their monodispersity. This work investigates the optimal reaction conditions and characterizes the optical properties.

Conjugated Polymer Nanoparticles toward In Vivo Theranostics – Focus on Targeting, Imaging, Therapy, and the Importance of Clearance

“…However, this strategy can only rarely be applied because conjugated monomers are often solid at the reaction temperature. This problem can be circumvented when using liquid nonconjugated monomers, where the resulting polymer can subsequently be converted into a π‐conjugated polymer . Similar approaches are also possible in dispersion polymerization .…”

Assemblies of Polyacrylonitrile-Derived Photoactive Polymers as Blue and Green Light Photo-Cocatalysts for Cu-Catalyzed ATRP in Water and Organic Solvents

“…However, recent reports point out that PAN can generate photoluminescence when dissolved at high concentrations or densely grafted from flat silica surfaces ( Jang et al, 2006 ; Zhou et al, 2016 ; Kopeć et al, 2020 ). Additionally, there are recent reports of chemical conversion of PAN into photoactive species via microwave ( Go et al, 2017 ), pyrolysis ( Cao et al, 2020 ) and hydrothermal reactions ( Ermakov et al, 2000 ; Sun et al, 2020 ), which all can induce the crosslinking or the hydrolysis of -C≡N, resulting in photoluminescent crosslinked nanoparticles or polymers. In particular, we recently reported the synthesis of visible light-absorbing photoluminescent polymers (PLPs) from PAN via a one-step hydrothermal reaction ( Sun et al, 2020 ).…”

Low-Temperature Synthesis of Carbon-Rich Nanoparticles with a Clickable Surface for Functionalization

“…Well-defined precursors may be synthesized by organic methods in a few synthetic steps. By introducing a series of consecutive sp-hybridized functional groups such as nitrile and polyynes, these precursors may be converted into carbon-rich material using an external stimulus. − Some reports show the success of using polyynes as precursors for the preparation of spherical carbon nanomaterials. , However, these procedures lead to micron-size materials or high polydispersity or require pyrolysis to generate the carbon-rich particles. In 2012, our group reported a room-temperature synthesis of fluorescent CNPs from organogel precursors .…”