No abstract

Hybrid polymeric materials incorporating carbon nanostructures or inorganic constituents stand as a promising class of materials exhibiting distinct but also complementary features. Carbon nanotubes have been proposed as unique candidates for polymer reinforcement; however, sustained efforts are further needed in order to make full use of their potential. The final properties of the reinforced polymer are controlled in part by the morphology and the eventual molecular orientation of the polymer matrix. In the present study, multiwall carbon nanotubes (MWCNTs) were utilized in order to reinforce polyethylene terephthalate (PET) composites. The effect of CNTs on the crystallization and the orientation of the structurally hybridized polymeric material has been investigated from the perspective of assessing their impact on the final properties of a relevant nanocomposite product. Functionalized MWCNTs were used to achieve their optimal dispersion in the polymer matrix. The physical properties of the composites (i.e., crystallinity and orientation) were characterized via differential scanning calorimetry, X-ray diffraction, and polarized Raman microscopy. The addition of well-dispersed CNTs acted as a nucleation agent, increasing the crystallization of the polyethylene terephthalate matrix and differentiating the orientation of both CNTs and macromolecular chains.

The collection of surface‐enhanced Raman scattering (SERS) by silver nanocolloids was used to identify the critical micelle concentration (CMC) of three cationic surfactants in 0.5‐M NaCl solutions: hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and benzalkonium chloride. Despite structural similarity between the three test surfactans, differences of the shape and size of the respective micelles affected the corresponding SERS signals. The CMC values determined by this method agreed with the respective values measured by conventional methods, including fluorescence probing and electrical conductivity measurements. The potential for the application of SERS technique for low CMC determination without surface modification of silver nanoparticles by a Raman‐active molecule was also demonstrated.