We report a new class of functionalized polylutidine polymers that are prepared by chemical vapor deposition polymerization of substituted (1,4)benzeno(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 well-defined 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, ζ-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-lutidinylene-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.
Bibliographical noteFunding Information:
The authors acknowledge funding from the Helmholtz Association within the BioInterfaces Program of the KIT. C.H., S.B.; and J.L. thank the German Science Foundation (DFG) for financial support within the frame of the collaborative research center SFB 1176 (project B3). J.L. and R.K. acknowledge support from the Defense Threat Reduction Agency (DTRA) through Grant HDTRA1-12-1-0039 as a part of the interfacial dynamics and reactivity program. J.L. and R.K. are also grateful to the Army Research Office (ARO) for funding provided under Grant W911NF-11-1-0251. Annamarija Raic is gratefully acknowledged for designing the frontispiece artwork.
- chemical vapor deposition
- click chemistry
- reactive coatings