Dec 5, 2024
3:15pm - 3:30pm
Hynes, Level 1, Room 110
Hemant Kumar1,Rabibrata Mukherjee1,Pallab Banerji1
Indian Institute of Technology Kharagpur1
Hemant Kumar1,Rabibrata Mukherjee1,Pallab Banerji1
Indian Institute of Technology Kharagpur1
Two polymers that are immiscible when dissolved in a mutual solvent undergo phase separation during spin coating on a non-wettable surface. Rapid evaporation of the solvent creates Marangoni stresses leading to instability between the two polymer interfaces. Phase separated morphology is influenced by several factors such as type of solvent, respective solubility of polymers, relative molecular weight, ratio of the polymers, type of the substrate and also its favored affinity towards the constituents. In this article surface morphology of as cast thin films of PS/PMMA polymer blend of composition 1:1 (ratio of PS & PMMA in solution, v/v) has been modulated by addition of CdS quantum dots. While presence of nano particles in a homo-polymer film makes the film stable against dewetting, in a blend it can also alter film morphology. To understand the influence of quantum dots in polymer blends, the morphology of spin coated PS/PMMA blend films was studied first. Upon addition of QDs, changes in morphology of the polymer blend film was studied with an Atomic Force Microscope. The Quantum dot concentration (C
QDs) was varied between 0% to 10%. As the concentration of QDs increases, size of PS domain is found to increase. In contrast, annealing above glass transition of PS/PMMA suppresses the PMMA domains in the particle free film. Blends containing QDs show a similar change in morphology, upon annealing, as QD free films. Photoluminescence (PL) spectra of the QD containing blend is similar to the particle free blend film, revealing that upon addition of QDs in a blend, optical properties remain unaltered. Moreover, the slight narrowing of PL spectra on addition of QDs in the blend has been observed which is attributed to the scattering effect in the blend. RAMAN spectra indicate the presence of particles in the PS as well as PMMA domains.