| Filled polymer systems make up a broad field with the potential to create a myriad of hybrid materials. The modification of polymer systems with inorganic particles enables the manipulation of mechanical (increased strength of the polymer matrix), electrical (changes in conductivity), and optical (changes in index of refraction) properties of these materials. The number of potential changes in materials properties of polymers via inorganic fillers is only limited by the imaginations of the people studying them. Exploration of the fundamental interactions between system components allows for an understanding not only of what these systems are and what they can do, but also of how they form.; We focus on the inclusion of hard, spherical nanoparticles in a block copolymer matrix. Block copolymers are well-known to self-assemble into a variety of morphological templates. When a tertiary phase, such as the particles, is introduced into the block copolymer, the system must strive to minimize its free energy via integration or expulsion of the particles. Included particles could self-assemble, using the block copolymer as a template, allowing for the creation of complex devices. Our experimentation aims to understand the fundamental relationships which drive these systems to their equilibrium morphologies. A methodology for creating these systems is described, integrating styrene-compatibilized particles into a styrene/ethylenepropylene block copolymer. Although the particles are derivatized to be compatible with the styrene phase of the block copolymer, they do not achieve exclusive dispersion through that phase, instead pinning at the interphase, or expelling into agglomerates or the ethylenepropylene phase.; Our results indicate the free energy of the system is undergoing a much more complex thermodynamic balance than was expected, and the translational entropy of the particles is sacrificed in order to achieve an equilibrated system. The potential driving forces and interactions involved in the assembly of particles within a block copolymer matrix are discussed, focused specifically on the surfactant-particle and surfactant-particle-block copolymer interactions. Possibilities for improvement and expansion of these composite systems are considered, with the goal that the knowledge gained here can serve as a stepping stone for greater understanding of the phenomenon of self-assembly in these systems. |
