Nanosecond pulse-driven atmospheric-pressure plasmas for polymer surface modifications: Wettability performance, insulation evaluation and mechanisms

Rapid Evaluation of Material Surface Modification by a Dielectric Barrier Discharge Based on Fluorescence Coloring and Image Processing Technologies

“…Compared with the untreated samples, the content of C on the PMMA surface after the DBD treatment with HMDSO decreases from 72.3 to 19.3%, and the contents of O and Si increase from 22.8 to 55.1% and 4.0 to 25%, respectively. It further verifies that fragments of HMDSO are deposited on the material surface and cover the methyl groups of PMMA, resulting in the decrease of C and the increase of O and Si . After the fluorescence-assisted DBD treatment, the contents of N and S increase from 0.4 to 6.6% and 0.2 to 2.3%, respectively, verifying the attachment of the fluorescent agent on the material surface.…”

“…The fragmentation of HMDSO and the deposition of the Si-containing film on the material surface have been proved by previous work . Normally, the deposited film is extremely thin, and it is not easy to be identified, especially on the transparent PMMA sample, as shown in Figure a.…”

“…It further verifies that fragments of HMDSO are deposited on the material surface and cover the methyl groups of PMMA, resulting in the decrease of C and the increase of O and Si. 35 After the fluorescence-assisted DBD treatment, the contents of N and S increase from 0.4 to 6.6% and 0.2 to 2.3%, respectively, verifying the attachment of the fluorescent agent on the material surface. Based on the analysis mentioned above, the mechanism of the fluorescence-assisted DBD modification is illustrated in Figure 15.…”

“…As shown in Figure b, the surface of untreated PMMA is dominated by organic characteristic peaks containing C–C, CO, C–O, C–H, etc., which are mainly derived from the methyl and carboxyl in PMMA. After the DBD treatment with HMDSO, the chemical bonds of the original groups on the PMMA surface are broken due to the collision of high-energy particles from plasma, and the fragments of HMDSO are grafted on the material surface to form the Si-containing film . Consequently, the original C-containing organic peaks are greatly reduced, and the functional groups Si–O–Si and Si-CH x are introduced.…”

“…After DBD treatment with HMDSO, a dense film with a large amount of spherical particles appears on the material surface and covers the original surface of PMMA, which indicates that the Ar/HMDSO plasma fabricates a new film on the PMMA surface; by contrast, after treatment by the fluorescent-assisted DBD, the spherical particles are bound together and connected to each other in clusters, indicating that the addition of the fluorescent agent promotes the accumulation of spherical particles and verifying the good mixing of HMDSO with the fluorescent agent. It is noted that the new structure with spherical particles and clusters increases the surface roughness, which reduces the contact area and the van der Waals force between the water drop and the surface, leading to the increase in WCA. , …”