Changing the wettability and barrier properties for bioplastics by plasma generated amorphous carbon coatings

通过等离子体产生的无定形碳涂层改变生物塑料的润湿性和阻隔性能

• 批准号: 387344394
• 负责人: Professor Dr. Stefan Wehner, since 11/2017
• 金额: --
• 依托单位: Abteilung Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387344394?language=en
• 关键词: Changing; wettability; barrier; properties; bioplastics

The project aims to modify the surface of four different biopolymers (PLA, PHBV, PCL, PBAT) via DLC coating to change their gas barrier properties and their wettability. The special feature of this approach is not to use as usual an additional (heterogeneous) interlayer, but to optimize and adjust the plasma deposition parameters of the DLC coating itself for the two crucial factors of good adhesion and flawless DLC.A commercially available DLC coating, namely FMC (flexible medical carbon), which is particularly applicable on soft substrates, is applied on the above mentioned biopolymer foils by Rf-PECVD process. The properties of the coating will be varied by adjustment of the plasma parameters (i.e. Rf power, deposition time, etc.) and analyzed with regard to film thickness, (micro)roughness (AFM and SEM measurements), chemical composition and environment by means of XPS, NEXAFS and FTIR spectroscopy, water vapor permeability and surface wettability by contact angle measurements.We will mainly use relatively thin coatings in the narrow range of 20 - 50 nm due to several reasons. Firstly, in this range the contact angle will differ significantly, i.e. it will be smallest in comparison to the original biopolymer surface, and will differ from thicker coatings, as well. In this range a minimum for the contact angle is expected. Second, we assume that even such thin coatings already provide a flawless and almost closed DLC layer, with all its benefits. This means, gas barrier properties are significantly enhanced in comparison to uncoated material. Besides, the thin and flexible coating (which goes along a low intrinsic stress within the DLC layer) may avoid the formation of micro cracks, which would diminish the barrier properties.During the plasma process the sample position towards the plasma source plays a crucial role. Its impact is to be studied for the FMC coating on the chosen biopolymeric materials. Starting from the two known extremes, the r-DLC type (sample directed towards the plasma source) and the f-DLC type (sample opposite to the plasma source), the sample orientation will be varied between these two possibilities during the depostion. The flexible DLC coating type FMC is applied by rotating the sample in front of the plasma source meaning so to say a repetitive sample position between the two extremes. The resulting coating properties especially water vapor barrier properties and wettability are to be studied and evaluated with respect to changing deposition parameters.

该项目旨在通过DLC涂层对四种不同的生物聚合物（PLA，PHBV，PCL，PBAT）进行表面改性，以改变其阻气性和润湿性。这种方法的特点是不像通常那样使用附加的这意味着，DLC涂层本身的等离子体沉积参数的优化和调整是为了获得良好的附着力和无缺陷的DLC这两个关键因素。通过Rf-PECVD工艺将特别适用于软基片的柔性医用碳（flexible medical carbon）施加在上述生物聚合物箔上。通过调整等离子体参数（即RF功率、沉积时间等），并通过XPS、NEXAFS和FTIR光谱分析了薄膜厚度、（微）粗糙度（AFM和SEM测量）、化学成分和环境，通过接触角测量分析了水蒸气渗透性和表面润湿性。由于多种原因，我们将主要使用20 - 50 nm窄范围内的相对较薄的涂层。首先，在该范围内，接触角将显著不同，即，与原始生物聚合物表面相比，接触角将最小，并且也将不同于较厚的涂层。在该范围内，预期接触角最小。其次，我们假设即使如此薄的涂层也已经提供了一个完美的、几乎封闭的DLC层，并具有其所有的优点。这意味着，与未涂覆的材料相比，气体阻隔性能显著增强。此外，薄而柔韧的涂层（其沿着DLC层内的低内应力）可以避免微裂纹的形成，微裂纹会降低阻挡性能。在等离子体处理过程中，样品朝向等离子体源的位置起着至关重要的作用。将研究FMC涂层对所选生物聚合物材料的影响。从两个已知的极端开始，即r-DLC类型（样品朝向等离子体源）和f-DLC类型（样品与等离子体源相对），样品取向将在沉积期间在这两种可能性之间变化。柔性DLC涂层类型FMC通过在等离子体源前面旋转样品来施加，这意味着在两个极端之间重复样品位置。将研究和评价所得涂层性能，特别是水蒸气阻隔性能和润湿性，相对于改变沉积参数。