Amphiphilic Polymer Structure Confers Function for Formulation Engineering

Prof. Paschalis Alexandridis

Block copolymers exhibit an innate ability to organize from the nanoscale across to the mesoscale. Selective solvents provide valuable degrees of freedom for controlling the morphology and, hence, structure/property relationships; furthermore, solvents can dramatically affect the molecular mobility and the dynamics of structural transformations. The presentation will utilize research findings on “model” amphiphilic block copolymers of the poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) family, commercially available as Pluronics or Poloxamers, to discuss: (1) the basic self-assembly elements, i.e., micelles, in terms of the thermodynamics and interactions underlying their formation and disassembly in aqueous solvents (selective for PEO), and their nano-scale structure and dynamics, (2) the adsorption of block copolymers on surfaces macroscopic and nanoscale, hard and soft, and how the adsorbed layer structure can be related to the polymer organization in the bulk solution, (3) ordered micelles, i.e., lyotropic liquid crystal structures, in the context of their range of stability as affected by the block copolymer conformation and various additives (e.g., glycols, nanoparticles), and their structural transformations under shear, and (4) how the equilibrium phase behavior can inform processing paths for the preparation of kinetically stabilized emulsions and nanoparticles, and templates for nanomaterials synthesis. The self-assembly properties of PEO-PPO block copolymers in selective solvents are compared to those of low-molecular weight nonionic surfactants, and to block copolymers organizing in the absence of solvents.

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Paschalis Alexandridis utilizes molecular interactions and supramolecular assemblies to develop products with desired properties and function, and processes that are environment friendly and energy efficient. Ongoing projects address structuring via self-assembly and directed assembly, block copolymers, perfluorinated surfactants, ionic liquid solvents, polymer dissolution, biomass processing, and plastics recycling. He has worked with industry to address product and process issues involving complex fluids, soft materials, and surfaces, for example, formulation of waterborne inks for improved pigment deposition, prediction of long-term performance of biomedical cross-linked polymer gels, and control of adhesion during plastics processing.

Prof. Alexandridis has authored over 165 peer-reviewed articles (published in 60 different journals) and 65 proceedings (Google Scholar citations >17,400 and h-index = 67). He is the editor of two books and co-inventor of six U.S. patents on pharmaceutical formulations, superabsorbent polymers, and nanomaterial synthesis. He has served as Director of Graduate Studies in Chemical Engineering, Co-Director of the Materials Science and Engineering program, and Associate Dean for Research and Graduate Education in the School of Engineering and Applied Sciences. Alexandridis received his PhD in chemical engineering from MIT in 1994, and joined UB in 1997 following postdoctoral research in polymer and surfactant physical chemistry at Lund University in Sweden.

At UB, Alexandridis has developed and taught courses such as “We All Live in a Material World” and “Molecular Nanotechnology and Bionanotechnology” (freshman-level seminars), “Colloid and Surface Phenomena”, “Introduction to Polymers”, and “Petroleum Engineering” (elective courses), and “Product Design” (required capstone design course). He has mentored in research over 70 graduate and 70 undergraduate students.

Prof. Alexandridis is an elected Fellow of the American Institute of Chemical Engineers (AIChE) and the American Association for the Advancement of Science (AAAS). He has received numerous awards including the American Chemical Society (ACS) Schoellkopf Medal, Bodossaki Foundation Academic Prize in Applied Science, SUNY Chancellor’s Awards for Excellence in Scholarship and Creative Activity and in Teaching, and UB’s inaugural Excellence in Graduate Student Mentoring Award. Alexandridis has served as chair of AIChE Area 1C: “Interfacial Phenomena” and on the executive committee of the ACS Division of Colloid and Surface Chemistry. He is currently serving as co-Editor-in-Chief of the International Journal of Molecular Sciences and Review Editor of the Journal of Surfactants and Detergents.