Abstract

We report a new class of functionalized polylutidine polymers that are prepared by chemical vapor deposition
polymerization of substituted [2](1,4)benzeno[2] 2,5)pyridinophanes. To prepare sufficient amounts of monomer for CVD polymerization, a new synthesis route for ethynylpyridinophane has been developed in three steps with an overall yield of 59%. Subsequent CVD polymerization yielded welldefined films of poly(2,5-lutidinylene-co-p-xylylene) and poly(4-ethynyl-2,5-lutidinylene-co-p-xylylene).

All polymers were characterized by infrared reflection–absorption spectroscopy,ellipsometry, contact angle studies, and X-ray photoelectron spectroscopy. Moreover, z-potential measurements revealed that polylutidine films have higher isoelectric points than the corresponding poly-xylylene surfaces owing to the nitrogen atoms in the polymer backbone. The availability of reactive alkyne groups on the surface of poly(4-ethynyl-2,5-utidinylene-co-p-xylylene) coatings was confirmed by spatially controlled surface modification by means of Huisgen 1,3-dipolar cycloaddition.

Compared to the more hydrophobic poly-p-xylylyenes, the presence of the heteroatom in the polymer backbone of polylutidine polymers resulted in surfaces that supported an increased adhesion of primary human umbilical vein endothelial cells (HUVECs). Vapor-based polylutidine coatings are a new class of polymers that feature increased hydrophilicity and increased cell adhesion without limiting the flexibility in selecting appropriate functional side groups.

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