Time of flight secondary ion mass spectrometry surface and in-depth study of degradation of nanosheet poly(L-lactic acid) films.

With the advent of novel fabrication technologies, free-standing poly(l-lactic acid) (PLLA) nanosheets have been shown to have enhanced performance over their micro- or macroscale equivalents as tissue engineering and drug delivery constructs. In the present research, the authors investigated the surface degradation behavior of PLLA films as a function of confinement to a quasi-two-dimensional structure, and the degradation behavior of nanoscale PLLA films as a function of the initial molecular weight and depth, using time-of-flight secondary ion mass spectrometry. The authors found that nanofilms exhibit less segregation of shorter chains to the surface than microfilms, due to the constrained geometries of these morphologies.