Study of the water structure in poly(methyl methacrylate-block-2-hydroxyethyl methacrylate) and its relationship to platelet adhesion on the copolymer surface

Abstract

The water structure and platelet compatibility of poly(methyl methacrylate (MMA)-block-2-hydroxyethyl methacrylate (HEMA)) were investigated. The molecular weight (Mn) of the polyHEMA segment was kept constant (average: 9600), while the Mn of the polyMMA segment was varied from 1340 to 7390. The equilibrium water content of the copolymers was found to be mainly governed by the HEMA content. The water structure in the copolymers was characterized in terms of the amounts of non-freezing and freezing water (abbreviated as W_nf and W_fz, respectively) using differential scanning calorimetry. It was found that the W_nf for the copolymers were higher than those estimated from the W_nf for the HEMA and MMA homopolymers and that the amount of excess non-freezing water depended on the polyMMA segment length. In addition, X-ray diffraction analysis revealed that some of the copolymers had cold-crystallizable water. These facts suggested that the polyMMA segments were involved in determining the water structures in the copolymers. Furthermore, the platelet compatibility of the copolymers was improved as compared to that of the HEMA homopolymer. It was therefore concluded that the platelet compatibility of the copolymer was related to the amount of excess non-freezing water.

Keywords:

• water structure
• HEMA-based block copolymer
• differential scanning calorimetry
• platelet compatibility
• non-freezing water

Acknowledgments

We thank Prof. Makoto Ohba, Tokai University, for his assistance with the NMR measurements. We also appreciate the technical support provided by the Education and Research Support Center at Tokai University during SEM observation of the adherent platelet.

Disclosure statement

No potential conflict of interest was reported by the authors.