Stage I (2022) of the project had as specific objective the synthesis and characterization of oligomers with conjugated structure and star/branched architecture, containing triphenylamine units connected by different π-spacers, and their electropolymerization in order to obtain microporous conjugated polymers.

In the stage I, the following results were achieved:

• Synthesis of three oligomers with p-phenylene-vinylene and p-phenylene-vinylene-ethynylene conjugated structures, and star-shaped architectures. The synthetic approach involved a convergent synthesis method, via coupling reactions between derivatives possessing linear structure (containing peripheral triphenylamine units) and a central triphenylamine unit.
• Structural confirmation of the obtained oligomers was achieved through NMR spectroscopy (¹H and ¹³C) and FT-IR techniques, elucidating their chemical composition. UV-Vis and fluorescence spectroscopies were employed to assess their optical properties, while cyclic voltammetry helped to investigate their electrochemical features. These experiments highlighted the influence of the π-spacers between the triphenylamine units on the physico-chemical properties of the oligomers.
• The optimization step of the electropolymerization protocols involving the oligomers resulted in the identification of optimal electrodeposition conditions; at the end of the successive electro-oxidation/reduction processes, conjugated polymers were obtained as uniform coatings /without cracks, adhering to the working electrode used;
• Structural characterization of the obtained conjugated polymers was achieved by using FT-IR spectroscopy, while their optical properties were investigated by using UV-Vis and fluorescence spectroscopies. Electrochemical analysis of the electrodeposited polymer layers revealed good electrochemical stability and color shifts upon applied potential, prompting evaluation of their electrochromic properties. Surface morphology of the electrodeposited coatings was scrutinized via SEM spectroscopy.

Part of the obtained results were disseminated in form of 1 presentation at an international scientific event. 

Stage II (2023) of the project had as specific objective the synthesis and characterization of oligomers with conjugated structure and star/branched architecture, used as precursors in polymerization processes (electrochemical and emulsion) with the aim of obtaining microporous conjugated polymers and the further evaluation of their efficiency in the detection of nitroaromatic harmful derivatives.

In the stage II, the following results were achieved:

• Synthesis of two oligomers with conjugated structure and star/branched architecture, containing triphenylamine units (peripheral and central) and benzothiadiazole. Structural confirmation of the synthesized oligomers was performed by using ¹H NMR and FT-IR spectroscopies; the optical properties were investigated by UV-Vis and fluorescence spectroscopies, while the cyclic voltammetry helped to evaluate their electrochemical characteristics. The structure-property correlations made on the basis of the obtained experimental data highlighted the influence of the π-spacers between the triphenylamine units;
• Synthesis of two series of polymers by using two distinct polymerization protocols: electrochemical polymerization and emulsion polymerization; the optimization of polymerization conditions leads to the obtaining of polymers both in the form of uniform layers adhering to the support, and in powder form (soluble and insoluble in common organic solvents). FT-IR spectroscopy confirmed the structure of the obtained polymers, while optical properties were evaluated both in solid-state and solution mediums.
• The surface morphology evaluation by using SEM spectroscopy revealed insights into the organization/ordering of polymer chains based on precursor structures and the significant impact of the polymerization method used. The BET gas adsorption isotherms allowed a more detailed assessment of porosity.
• The evaluation of the detection capability for nitroaromatic derivatives via electrochemical methods and fluorescence spectroscopy demonstrated that obtained polymers, either in the form of electrogenerated layers or as solid particles in solution, can function effectively as receptors for 2,4-dinitrotoluene and trinitrophenolic acid.

Part of the results obtained in the Stage II were disseminated in form of 2 presentations and 1 poster presentation at 3 international scientific events, and 2 scientific papers (1 published and 1 under evaluation) in ISI journals.