Abstract
This work is mainly concentrated on two different topics. The first topic is the development of methods for solving the cracking problem in latex films. The second topic is the development of a new technique, called Infrared Assisted Evaporative Lithography (IRAEL), which is used for the patterning of polymeric surfaces. The addition of carbon nanotubes is proposed as a method to increase the critical cracking thickness of hard latex films. It was found that larger latex particles lead to higher critical thicknesses. Furthermore, the addition of pure poly(vinyl-pyrrolidone) (PVP) and MWNT/ PVP dispersion in latex resulted in higher critical thicknesses (up to 30 % higher). A second method developed to prevent latex cracking is the use of infrared (IR) radiation. Thick, crack-free films were made from a hard latex. It was found that the rate of particle sintering under IR radiation is significantly greater than in an oven at 60C and is faster when IR absorbing materials were used. No plasticizers were required, and no volatile organic compounds (VOCs) were released in the process. IRAEL combines the principles of standard evaporative lithography with the infrared assisted latex particle sintering method. A mask with holes is placed under an IR source to modulate the evaporation rate across a film surface. Experiments show that a lower distance between the mask and film, a larger pitch (with a maximum at 5 mm), higher solids volume fraction (with a maximum at 0. 37) and a higher film thickness lead to higher peak-to-valley heights of the raised features. In addition it is shown that the peak-to-valley height is affected by the substrate on which the latex film was cast. IRAEL has many advantages compared to other common patterning techniques. Specifically, a broad range of features can be achieved, there is no use of solvents, the energy consumption is lower compared to other techniques, and it is applicable to a variety of substrates. Also it is a simple, fast and cheap technique. Furthermore, the infrared heating of the latex films above the glass transition temperature of the polymer makes possible the film formation of hard latexes as opposed to the standard evaporative lithography, which is applicable only to soft particles.