Polymerization behavior and polymer properties of eosin-mediated surface modification reactions

• Published in: Polymer (Guilford) 2008-10, Vol.49 (22), p.4762-4768
• Main Authors: Avens, Heather J., Randle, Thomas J., Bowman, Christopher N.
• Format: Article
• Language: English
• Subjects: Applied sciences; Aqueous monomer formulations; Exact sciences and technology; Physicochemistry of polymers; Polymerization; Polymers and radiations; Surface-mediated polymerization; Visible light photopolymerization
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2008.08.054

Surface modification by surface-mediated polymerization necessitates control of the grafted polymer film thicknesses to achieve the desired property changes. Here, a microarray format is used to assess a range of reaction conditions and formulations rapidly in regards to the film thicknesses achieved and the polymerization behavior. Monomer formulations initiated by eosin conjugates with varying concentrations of poly(ethylene glycol) diacrylate (PEGDA), N-methyldiethanolamine (MDEA), and 1-vinyl-2-pyrrolidone (VP) were evaluated. Acrylamide with MDEA or ascorbic acid as a coinitiator was also investigated. The best formulation was found to be 40wt% acrylamide with MDEA which yielded four to eightfold thicker films (maximum polymer thickness increased from 180nm to 1420nm) and generated visible films from fivefold lower eosin surface densities (2.8 versus 14 eosins/μm2) compared to a corresponding PEGDA formulation. Using a microarray format to assess multiple initiator surface densities enabled facile identification of a monomer formulation that yields the desired polymer properties and polymerization behavior across the requisite range of initiator surface densities. [Display omitted]