PLA and PHA are two very promising biomaterials being extensively used in medical and pharmaceutical fields. However, their hydrophobic surfaces limit their use in many biomedical applications. We used UV-assisted photografting in ethanol to grow hydrophilic polymers (e.g., poly(acrylic acid) and polyacrylamide) from the surfaces of PLA, PHA, and PLA/PHA blend films. The modified surfaces were characterized using water contact angle goniometry and ATR-FTIR spectroscopy, while toughness, Young's modulus, % elongation at break, % crystallinity, and tensile strength of unmodified and surface-modified films were also studied. The penetration of monomers into the bulk of the surface-modified films was characterized using transmission FTIR microspectroscopy. Microtomed sections of the surface modified films were placed in a diamond compression cell to perform the FTIR microspectroscopic analyses. Significant monomer penetration into the bulk of the surface modified films was observed, and certain mechanical properties were affected. The photografting was then conducted in water instead of ethanol and demonstrated favorable surface properties (enhanced wettability) without significantly affecting the bulk properties.