This investigation highlights rationale of vaporized solvent bonding for fabrication of transparent polymers such as polymethyl methacrylate (PMMA) in terms of optical transparency and bond strength. Vaporized solvent bonding is employed to fabricate the polymer, and its bonding characteristics with appropriate solvents are analyzed. It is observed that chloroform exhibits superior bonding characteristics in comparison with other solvents such as acetone, ethanol, and dichloromethane. In order to see the effect of prior surface modification carried out by ultraviolet (UV) irradiation and low-pressure plasma, surface energy of the polymer was estimated. It is observed that due to surface modification of PMMA by UV irradiation and low-pressure plasma, surface energy of the polymer increases considerably. However, due to exposure under UV irradiation and low-pressure plasma, molecular weight of PMMA decreases and atomic force microscopy (AFM) studies reveal that the topography of PMMA changes significantly resulting in deterioration of vaporized solvent bonding strength. Therefore, in the case of vaporized solvent bonding, increase in surface energy of the polymer is not a primary factor rather retention of molecular weight is more necessary.
A. V. Akhil, Raj, D. D. D., Raj, M. K., Bhat, S. R., Akshay, V., Shantanu Bhowmik, Ramanathan, S., and Ahmed, S., “Vaporized solvent bonding of polymethyl methacrylate”, Journal of Adhesion Science and Technology, pp. 1–16, 2015.