Surface modification of poly (lactic acid) with an improved alkali-acid hydrolysis method

• PLA is modified using an improved alkali-acid hydrolysis method.
• Adding of citric acid evidently improves hydrophility and surface roughness of PLA.
• Surface modification ability of calcium hydroxide is identified.

In this article, an improved alkali-acid hydrolysis method was used to enhance the hydrophilicity of poly (l-lactic acid) (PLLA). Compared with the traditional alkali hydrolysis method, whether the alkali solution was sodium hydroxide or calcium hydroxide, the new surface modification method using citric acid as the wash solution brought a significant decrease of PLLA film׳s surface water contact angle and a dramatic increase of PLLA׳s surface roughness in a short time, which indicates that this alkali-acid hydrolysis method can effectively improve the hydrophilicity of PLLA. The evident surface modification effect can be mainly attributed to the catalytic ability of the citric acid׳s carboxyl group to cleave polyester׳s ester bond.

An improved surface alkali-acid hydrolysis method is used to enhance the hydrophilicity of poly (l-lactic acid) (PLLA). By add a wash process of citric acid, the surface water contact angle of PLLA film significantly decreases while the surface roughness of the film dramatically increases.Figure optionsDownload as PowerPoint slide