Stereocomplexation: From molecular structure to functionality of advanced polylactide systems

The present review summarizes the recent advances in the field of stereocomplexation of advanced polylactide (PLA)-based systems. As a widely-used biodegradable polymer, PLA has two crystallizable enantiomeric counterparts poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) that can be blended to form a highly-packed 31 crystalline structure known as stereocomplex formed because of the mutual diffusion and hydrogen bonding and/or Van der Waals interactions between the chains. The presence of stereocomplex crystals (SCCs) allows to modulate and adjust material properties such as static- and dynamic-mechanical, thermal performance, and degradation properties for biomedical applications. Amongst the most influential factors in SCCs formation and/or increasing its fraction, we have comprehensively discussed the effects of (i) the molecular weight of the components (mutual diffusion effect) along with the processing methods applied for the formation of SCCs, (ii) incorporating different nucleating agents/multifunctional nanoparticles to control and/or improve stereocomplexation, and (iii) copolymerization that increases the possibility of SCCs formation along with toughening purposes. Finally, the mechanisms responsible for governing the control of SCC formation are explained in detail and the prospects in stereocomplexation in PLA multifunctional systems and their advanced engineering applications are elucidated.