Film Formation of Poly (methyl methacrylate) Latex With Pyrene Functional Poly (divinylbenzene) Microspheres Prepared by Click Chemistry S  aziye Ug ˘ ur, 1 O ¨ nder Yargı, 1 Yasemin Yu ¨ ksel Durmaz, 2 Bu ¨ nyamin Karago ¨ z, 2 Niyazi Bıc ¸ ak, 2 Yusuf Yag ˘ cı, 2 O ¨ nder Pekcan 3 1 Department of Physics, Istanbul Technical University, Maslak, 34469, Istanbul, Turkey 2 Department of Chemistry, Istanbul Technical University, Maslak, 34469, Istanbul, Turkey 3 Faculty of Arts and Science, Kadir Has University, Cibali, 34320, Istanbul, Turkey This work reports on the application of steady state fluorescence (SSF) technique for studying film forma- tion from poly(methyl methacrylate) (PMMA) latex and poly(divinylbenzene) (PDVB) microsphere composites. Pyrene (P) functionalized PDVB cross-linked spherical microspheres with diameters of 2.5 lm were synthe- sized by using precipitation polymerization technique followed by click coupling reaction. The diameter of the PMMA particles prepared by emulsion polymeriza- tion were in the range of 0.5–0.7 lm. PMMA/PDVB composite films were then prepared by physically blending of PMMA latex with PDVB microspheres at various composition (0, 1, 3, 5, 10, 20, 40, and 60 wt%). After drying, films were annealed at elevated tempera- tures above T g of PMMA ranging from 100 to 2708C for 10 min time intervals. Evolution of transparency of the composite films was monitored by using photon trans- mission intensity, I tr . Monomer (I P ) and excimer (I E ) flu- orescence intensities from P were measured after each annealing step. The possibility of using the excimer-to- monomer intensity ratio (I E /I P ) from PDVB micropar- ticles as a measure of PMMA latex coalescence was demonstrated. Diffusion of the PMMA chains across the particle–particle interfaces dilutes the dyes, increasing their separation. The film formation stages of PMMA latexes were modeled by monitoring the I E /I P ratios and related activation energies were determined. There was no observable change in activation energies confirming that film formation behavior is not affected by varying the PDVB composition in the studied range. SEM images of PMMA/PDVB composites confirmed that the PMMA particles undergo complete coales- cence forming a continuous phase in where PDVB microspheres are dispersed. POLYM. COMPOS., 32:869– 881, 2011. ª 2011 Society of Plastics Engineers INTRODUCTION A number of methods including water-based emulsion, seeded suspension, nonaqueous dispersion polymerization, and precipitation polymerization were successfully employed for the preparation of monodisperse micro- spheres [1–4]. Among them, precipitation polymerization, which can be performed in the absence of any added sur- factant or stabilizer [5–12] appeared to be an attractive route to obtain microspheres with uniform size and shape. Typically, monodisperse and highly crosslinked poly(divi- nylbenzene) (PDVB) surfactant-free microspheres (with diameters between 2 and 5 lm) were prepared by using only monomer (commercial divinylbenzene, DVB55), rad- ical initiator (2, 2 0 -azobisisobutronitrile, AIBN), and sol- vent (acetonitrile) [5]. Interestingly, PDVB microspheres formed in this method contained significant residual dou- ble bonds in the particle and on the surface of the particle [13]. The residual double bonds located at the surface per- mitted further growth and modification of particles. The ‘‘click reactions’’ [14, 15], in particular Cu(I)-cata- lyzed 1,3-dipolar Huisgen cycloaddition reactions between an azide and an alkyne, have gained a great deal of atten- tion due to their high specificity and nearly quantitative yields in the presence of many functional groups. Recently, PDVB microspheres were functionalized [16] by polymeric chains using two click reactions, namely thiol-ene chemistry and azide-alkyne cycloaddition reac- tion. We also reported functionalization of PDVB micro- spheres by the copper-catalyzed Huisgen 1-3 dipolar cycloaddition click reaction with a small fluorescent mol- ecule-alkyne modified pyrene [17]. Polymer composites are often prepared by mixtures of two or more different kinds of particles in the dispersed state. Upon drying of the dispersion, both types of particles Correspondence to: Saziye UGUR; e-mail: saziye@itu.edu.tr Contract grant sponsor: Turkish Academy of Sciences (TUBA). DOI 10.1002/pc.21094 Published online in Wiley Online Library (wileyonlinelibrary.com). V V C 2011 Society of Plastics Engineers POLYMERCOMPOSITES—-2011