Andy Strickland

My research applies modeling and computer simulation to mechanically-assembled monolayers, or MAMs. As seen in the inset, these monolayers are created by first stretching the surface. UV light then establishes the grafting sites for the polymer layer to attach. Last, relaxing the extended surface brings the polymers together, thereby increasing the surface density beyond what may be attainable through self-assembly. MAMs have been shown to possess long-lasting superhydrophobic properties.(1)


Computer simulation of the grafted polymer layer (also known as a 'brush') using discontinuous molecular dynamics (DMD) allows a molecular-level analysis of the individual interactions between particles, which is impossible in laboratory experiments.

Thus, one can adjust system properties such as polymer chain length, grafted surface density, system temperature, particle-particle interaction strength and rate of surface relaxation (from low to high surface density). In turn, key system characteristics such as brush thickness and monomer density profile can be investigated explicitly.

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The second phase of my research has been the modeling and computer simulation of copolymer formation and performance. We define here a copolymer as a polymer of two components, A and B, of the form A_xB_1-x. Current research has shown that these copolymers can act as blend compatilizers and adhesion promoters due to the unique blockiness of the A and B components. We have researched a theoretical approach for copolymer formation first proposed by Khokhlov and coworkers -- a A-type homopolymer is placed in a poor solvent and then the outer shell of exposed monomers is "colored" to the B-component (see figure to the right). The blockiness of the resulting A-B copolymers can be adjusted by judicious choice of A- and B-solubility, system temperature, time allowed to react, weight percent (or ratio) of A and B. Additionally, researchers can vary the chain length, further adjusting blockiness.