Polymer/Carbon Nanotube Composite Film Formation: A Fluorescence Study € Onder Yargı, 1 S¸aziye U  gur, 2 € Onder Pekcan 3 1 Yildiz Technical University, Department of Physics, Esenler, 34210 Istanbul, Turkey 2 Istanbul Technical University, Department of Physics, Maslak, 34469, Istanbul, Turkey 3 Kadir Has University, Faculty of Arts and Science, Cibali, 34320, Istanbul, Turkey In this study, the effect of multi-walled Carbon nano- tube (MWNT) on film formation behavior of Polystrene (PS) latex film was investigated by using steady state fluorescence technique. Films were prepared by mixing of pyrene (P)-labeled PS latex with different amounts of MWNTs varying in the range between 0 and 20 wt%. After drying, MWNT containing films were separately annealed above glass transition temperature (T g ) of PS ranging from 100 to 270  C for 10 min. In order to moni- tor film formation behavior of PS/MWNT composites, Scattered light (I s ) and fluorescence intensities (I P ) from P were measured after each annealing step to monitor the stages of film formation. At 0–20 wt% range of MWNT content films, minimum film formation (T o ), void closure (T v ), and healing, (T h ) temperatures were determined. Void closure and interdiffusion stages were modeled and related activation energies were determined. It was observed that while void clo- sure activation energies increased, backbone activa- tion energies decreased as the percent of MWNT is increased in the composite films. POLYM. COMPOS., 35:817–826, 2014. V C 2013 Society of Plastics Engineers INTRODUCTION As a result of worldwide efforts by theorist and experi- mentalists, a very good understanding of the mechanisms of latex film formation has been achieved [1]. Tradition- ally, the film formation process of polymer latex is consid- ered in terms of three sequential steps: (i) water evaporation and subsequent packing of polymer particles (ii) deformation of the particles and close contact between the particles if their T g is less than or close to the drying temperature (soft or low T g latex). Latex with a T g above the drying temperature (hard or high T g latex) stays unde- formed at this stage. In the annealing of hard latex system, deformation of particles first leads to void closure [2, 3] and then after the voids disappear, diffusion across parti- cle–particle boundaries starts, i.e., the mechanical proper- ties of hard latex films evolve during annealing, after all solvent has evaporated and all voids have disappeared. (iii) Coalescence of the deformed particles to form a homoge- neous film [3] where macromolecules belonging to differ- ent particles mix by interdiffusion [5, 6]. This understanding of latex film formation can now be exploited to underpin the processing of new types of coat- ings and adhives. The blending of latex particles and inor- ganic nanoparticles provides a facile means of ensuring dispersion at the nanometer scale in composite coatings. Ever since the first scientific report of carbon nanotubes (CNTs) in 1991, these materials have attracted enormous interest owing to their potential applications in field- emission devices, electronics, fibers, composites, sensors, detectors, capacitors, hydrogen storage media, and fuel cells, among others [7]. As of January of 2004, 152 patents relating to nanotube applications had been issued, and another 274 were pending. Recent work by numerous groups has demonstrated how nanocomposites of polymers and CNTs offer the advantages of polymers, such as opti- cal clarity, viscoelasticity and good barrier properties, com- bined with the strength [8] and the high thermal and electrical conductivity [9] of CNTs. Seven patents have already been issued for CNT nanocomposites and fibers. Four of the most common processing routes for this class of nanocomposites are (1) in situ polymerization [10], (2) melt processing and extrusion [11], (3) casting from a common solvent [12], and (4) functionalization of the CNT by polymers [13]. Recently, nanocomposite films were pre- pared from CNTs that were functionalized with poly(vinyl alcohol) (PVA) to make them dispersible in water [14]. The PVA-functionalized CNTs were then dispersed in an aqueous PVA solution and cast to create a nanocomposite film with a PVAmatrix. This approach does not require emulsifiers or surfactants to disperse the CNTs. However, Correspondence to: € Onder Yargı; e-mail: yargi78@gmail.com DOI 10.1002/pc.22725 Published online in Wiley Online Library (wileyonlinelibrary.com). V C 2013 Society of Plastics Engineers POLYMER COMPOSITES—2014