Synthesis, characterization and luminescent properties of new copolymers of dimethacrylate derivatives of naphthalene-2,7- diol Beata Podkościelna a *, Agnieszka Lipke b , Barbara Gawdzik a and Marek Majdan b Synthesis and characterization of new type photoluminescent, bulk copolymers of 2,7-(2-hydroxy-3- methacryloyloxypropoxy)naphthalene (2,7-NAF.DM) with different vinyl comonomers (methyl methacrylate, 2- hydroxyethyl methacrylate, butyl acrylate, divinylbenzene, styrene and N-vinyl-2-pyrrolidone) are presented. The chemical structure of 2,7-NAF.DM was confirmed by NMR, GC-MS and elemental analysis. The copolymers were char- acterized by ATR and thermal (differential scanning calorimetry) analyses. Their luminescent properties were studied in terms of quantum efficiency (Φ abs ), which was shown to change in the range of 50–90% depending on the type of comonomer. It was found that the green-emitting species in these polymers can be excited directly by low-energy (400–520 nm) photoirradiation. These materials can be applied in the liquid or solid states in the form of powders, films or monoliths. Copyright © 2014 John Wiley & Sons, Ltd. Keywords: bulk copolymers; dimethacrylate; DSC; naphthalene-2,7-diol; NMR; photoluminescence INTRODUCTION Naphthalene derivatives, due to their unique luminescent prop- erties, have been investigated and used as fluorophores of luminescent materials, [1–3] polymer light-emitting diodes, [4,5] photo-voltaic and optical devices, [6–8] etc. Polynaphthalenes with different linkages in 1,4-, 1,5-, 2,6- and 2,7-positions have been used as conducting polymers. [9] Hohloch et al. reported the synthesis and electroluminescence properties of poly(2,6-naphthylenevinylene) derivatives with yellow–green emission. [8] They initiated work on the synthesis of several naphthalene containing polymers which were used as luminophores in optical devices. [10–12] Yamamoto and Lee also reported the preparation and chemical properties of π-conjugated poly(naphthalene-2,6-diyl)-type polymers with N atoms at all of the four o-positions. [13] Premachandran et al. stressed that many fluorescent dyes contained segments ob- tained from 2-naphthol units. Easily processable fluorescent polymers containing naphthol chromophores could have poten- tial applications in the production of high laser resistance mate- rials, laser dyes and fiber optic sensors. [14] Luminescent composite materials based on semiconductor nanocrystals with an ionic liquid-based polymer which possesses an acrylate group were prepared by Nakashima et al. [15] The focus of the present study is on new compounds derived from 2,7-(2-hydroxy-3-methacryloyloxypropoxy)-naphthalene (2,7-NAF.DM). [16] The copolymers were synthesized using differ- ent comonomers: methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), butyl acrylate (BA), divinylbenzene (DVB), styrene (ST) and N-vinyl-2-pyrrolidone (NVP). These comonomers were chosen because of their different chemical character, which depended on the presence of aromatic or aliphatic substituents in their structure. The choice of the comonomers was also dic- tated by the fact that they are active solvents, which makes po- lymerization easier. Moreover, their spatial distribution in the structure enables modification of the luminescent properties of polymers and, most importantly, prevents interaction between polymer chains that would otherwise result in agglomeration, which, in turn, would worsen luminescence. To summarize, we present new polymeric naphthalene deriva- tives, which in future have a chance to find application in the preparation of different luminophores. We also pay attention to the thermal properties of the investigated copolymers, taking into account their potential application as thermally resistant coatings. EXPERIMENTAL Preparation of compositions and their polymerization Detailed information about the synthesis of 2,7-NAF.DM was pre- sented elsewhere. [16] Briefly, this monomer was obtained from * Correspondence to: Beata Podkościelna, Department of Polymer Chemistry, Maria Curie-Skłodowska University, M. Curie Skłodowska Sq. 5, 20-031 Lublin, Poland. E-mail: beatapod@umcs.pl a B. Podkościelna, B. Gawdzik Department of Polymer Chemistry, Maria Curie-Skłodowska University, M. Curie Skłodowska Sq. 5, 20-031, Lublin, Poland b A. Lipke, M. Majdan Department of Inorganic Chemistry, Faculty of Chemistry, Maria Curie- Skłodowska University, M. Curie Skłodowska Sq. 5, 20-031, Lublin, Poland Research article Received: 8 September 2014, Revised: 13 November 2014, Accepted: 23 November 2014, Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/pat.3447 Polym. Adv. Technol. 2014 Copyright © 2014 John Wiley & Sons, Ltd.