Improved Hydrophilicity from Poly(ethylene glycol) in Amphiphilic Conetworks with Poly(dimethylsiloxane)

This paper focuses on the improvement of hydrophicility and water content of poly(dimethylsiloxane) (PDMS) by bonding a hydrophilic macromer, hydroxyl-terminated linear poly(ethylene glycol) (PEG), into a highly hydrophobic macromer, hydroxyl-terminated linear PDMS to prepare amphiphilic conetworks (APCNs) with the crosslinkers, tetraethoxysilane (TEOS) and bis[(3-methyldimethoxysilyl) propyl]-polypropylene oxide (BMPPO), which also functioned as a compatibilizer. Fourier transform infrared results clearly demonstrated the occurrence of the hydrolysis reactions between the terminal hydroxyl groups on the terminal of the two polymer chains and the alkoxy groups in TEOS and BMPPO. Differential scanning calorimetry results and X-ray diffraction obviously showed the presence of the two phases in the conetworks. The contact angle (CA) indicated the wettability of the conetworks increased in the surfaces, that is, CA values decreased significantly from 105 degrees in PDMS to 55 in the PEG/PDMS APCN (10/1 mol ratio), and the swelling degrees of the APCNs increased from ca. 0 to 60 % when the PEG/PDMS mol ratio was larger than 4/1. The APCNs with such high hydrophilicity and the good mechanical properties should be useful as biomaterials.