Preparation of hydrophilic poly(vinyl alcohol)-containing amphiphilic diblock copolymers and their self-association in water

A series of amphiphilic diblock copolymers (PVA(m)-b-PVPi(n): A(m)P(n) = A(82)P(6), A(72)P(26), and A(70)P(74)) with different block lengths of hydrophilic poly(vinyl alcohol) (PVA, A) and hydrophobic poly(vinyl pivalate) (PVPi, P) blocks were prepared. A(m)P(n )was synthesized from a poly(vinyl acetate)-b-P (PVAc-b-P) diblock copolymer by selectively hydrolyzing the pendant acetyl groups in PVAc. In water, A(m)P(n) polymers formed spherical polymer micelles with a PVPi core and a PVA shell due to hydrophobic interactions between the PVPi blocks. The hydrodynamic radius (R-h), light scattering intensity (LSI), and aggregation number (N-agg) of A(m)P(n) increased with increasing PVPi block length. Conversely, the critical micelle concentration (CMC) was reduced due to stronger hydrophobic interactions. This study promotes potential applications for A(m)P(n) micelles to be used as nanocarriers for hydrophobic anticancer drugs.