Flexible and hybrid electronics (FHE) are widely utilized from wearable to automotive applications. Instead of commonly used poly(ethylene terephthalate) (PET) film, bio-based and biodegradable polymer, poly(lactic acid) (PLA), is a most promising novel substrate alternative for FHE. From the point of heat curable conductive inks, the poor heat resistance and inherent brittleness are the major drawbacks of PLA. By increasing the PLA film crystallinity through orientation and annealing, its properties can be improved. Two commercial grades, standard PLA (PLA) and a high heat PLA (hhPLA), plus one stereocomplex PLA (scPLA) blend were used to compare PLA performance with different optical purities and crystallinity for printed FHE. Machine direction orientation (MDO), biaxial orientation (BO) and annealing improved the stability of the laboratory and pilot scale manufactured PLA films. MDO was more effective in improving stiffness and strength while BO resulted in more ductile behaviour. In hhPLA the crystallinity increased from 0% to 50% improving tensile strength by 83%, tensile modulus by 52% and strain at break from 3.7% to 114% with 3 × 3 BO and annealing. The scPLA blend contained homo- and stereocomplex crystallites and a double melting peak behaviour provided higher temperature stability through final melting at 220°C. Its optical transparency reached 95%, remaining high up to 250 nm wavelength. In roll-to-roll printing, the PLA and hhPLA films were dried at 100°C prior the printing and this decreased the MD elongation from 2.55% and 0.27% to 0.00–0.05%. The sheet resistance of printed silver was <40 mΩ/sq with additional drying for printed and hybrid integrated light-emitting diode (LED) foils. Printed LED foils on PLA had dimensional and electrical performance comparable to PET, even though lower drying temperatures were used.

从可穿戴设备到汽车应用，柔性和混合电子产品（FHE）均得到广泛利用。代替常用的聚对苯二甲酸乙二醇酯（PET）薄膜，聚乳酸（PLA）是生物基且可生物降解的聚合物，是FHE的最有希望的新型底物替代品。从可热固化的导电油墨的角度来看，差的耐热性和固有的脆性是PLA的主要缺点。通过定向和退火提高PLA膜的结晶度，可以改善其性能。使用两种商业级别的标准PLA（PLA）和高温PLA（hhPLA），以及一种立构复合物PLA（scPLA）共混物来比较印刷的FHE具有不同光学纯度和结晶度的PLA性能。机器方向方向（MDO），双轴取向（BO）和退火提高了实验室和中试规模生产的PLA膜的稳定性。MDO在改善刚度和强度方面更有效，而BO导致更多的延性行为。在hhPLA中，使用3×3 BO和退火，结晶度从0％增加到50％，拉伸强度提高83％，拉伸模量提高52％，断裂应变从3.7％提高到114％。scPLA共混物包含均相和立构复杂的微晶，双峰熔融行为通过在220°C下最终熔融提供了更高的温度稳定性。其光学透明度达到95％，在250 nm波长下仍保持很高的透光率。在卷对卷印刷中，PLA和hhPLA膜在印刷前在100°C下干燥，这将MD伸长率从2.55％和0.27％降低至0.00-0.05％。印刷银的薄层电阻为< 40mΩ/ sq，并额外干燥，用于印刷和混合集成的发光二极管（LED）箔。即使使用较低的干燥温度，在PLA上印刷的LED箔的尺寸和电气性能也可与PET媲美。