ORIGINAL PAPER Evaluation of blood cells and proteins spreading on imidic polymers containing alicyclic sequences Luminita Ioana Buruiana 1 & Andreea Irina Barzic 1 & Iuliana Stoica 1 & Camelia Hulubei 1 Received: 10 March 2016 /Accepted: 13 September 2016 # Springer Science+Business Media Dordrecht 2016 Abstract A new polyimide containing alicyclic units is in- vestigated in regard to a fully aromatic commercial one in order to assess their hemocompatibility. The rheological, structural, and surface properties of these two polyimides are analyzed by infrared spectroscopy and contact angle measure- ments. Flow activation energy of polyimide solutions is al- most doubled when passing from 8 to 16 %, as an indicative of chain entanglement which enhances film formation ability. The surface tension components are obtained using the Fowkes method, revealing a slightly lower polar component (20.19 mN/m) for the semi-alicyclic polyimide, comparative with the aromatic one (22.52 mN/m). The hemocompatibility is theoretically established from calculation of the spreading work of blood cells and proteins on the polymer surface. The reduced polarizability and high flexibility of the alicyclic units from the new polyimide lead to improved hemocompatibility, as observed from the higher cohesion of blood components with this sample surface, comparative with the aromatic one. Keywords Polyimide . Alicyclic . Rheology . Hemocompatibility Introduction Polymers with imidic structure represent an important catego- ry of high-performance materials owing to their high thermal and chemical resistance, combined with good mechanical, optical, and electrical properties [1–5]. In the past years, it has been demonstrated that these materials are biocompatible if suitable monomers are used in synthesis. Low polarizable and non-aromatic compounds with a certain degree of chain flexibility are preferred for preparation of imidic polymers since they reduce the charge transfer complex interactions, thus generating a high transparency and a smooth surface tension, the latter depending on the size, shape, and flexibility of the monomers [6, 7]. These features are essential in bio- medical applications, where a clear view through the polymer support and a reduced surface roughness facilitate the obser- vation of the biological components [8]. In some specific cases, like blood-contacting devices, they are expected not to adhere at the interface with the polymer. In this context, the investigations reported in the literature [9, 10] have pointed out that the utilization of dianhydrides with alicyclic structure not only maintains the thermal and chemical stability but also renders improved optical and surface features to the final im- idic material. Among them, 5-(2,5-dioxotetrahydrofuryl)-3- methyl-3-cyclohexenyl-1,2-dicarboxylic anhydride is a unique, flexible, and nonsymmetrical chemical structure, ren- dering new properties to the resulting compounds [11]. In addition, it has been proved to exhibit good biocompatibility with human organism, being used for preparation of tooth- conditioning products [12]. Therefore, it is expected that in- troduction of this type of alicyclic sequences into the main chain is helpful to obtain flexible polymer films with a re- duced polarizability and implicitly low absorption, thus ex- tending the applicability to biomedical fields. In this work, a polyimide containing alicyclic sequences is studied from the point of its structural and surface features, in order to check its suitability as a hemocompatible material. The structure of the synthesized compound was analyzed by Fourier transform infrared spectroscopy (FTIR). Surface ten- sion components were determined from contact angle data * Andreea Irina Barzic irina_cosutchi@yahoo.com 1 “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, Iasi 700487, Romania J Polym Res (2016) 23:217 DOI 10.1007/s10965-016-1110-6