Creating ultrathin, uniform PLGA membranes through self-packaging on free-standing liquid films

Conventional thin film fabrication methods often face challenges such as long and multi steps fabrication procedures and material damage during detachment from solid substrates. This problem is even more evident in case of biomaterials effectively limiting their biomedical and commercial applicability. To address this problem, we propose a self-assembling film formation process that uniquely combines dynamic mechanical iris manipulation with a thin liquid film (TLF) as a hosting layer. This approach enables the creation of poly-lactic-co-glycolic acid (PLGA) membranes directly at the freestanding TLF's liquid interface. Capillary leveling ensures ultrathin uniform and freestanding PLGA membrane formation, while a collapse of the supporting liquid film avoiding a potentially damaging detachment step. For full and accurate characterization of these films, Digital Holography (DH) has been utilized. Holographic monitoring enables real-time thickness mapping of liquid films, thereby providing interface evolution information during PLGA membrane formation. It allows the implementation of closed-loop operation, e.g. forced drainage to shorten the waiting period before membrane collection. This innovative and programmable method is highly suitable for producing intact polymer films, opening new avenues for drug delivery and various biomedical applications.