Surface Activation of Poly(Methyl Methacrylate) with Atmospheric Pressure Ar + H2O Plasma

Abstract

The atmospheric pressure of Ar + H 2 O plasma jet has been analyzed and its effects on the poly(methyl methacrylate) (PMMA) surface has been investigated. The PMMA surface treatment was performed at a fixed gas flow-rate discharge voltage, while varying the plasma treatment time. The Ar + H 2 O plasma was studied with optical emission spectroscopy (OES). Optimum plasma conditions for PMMA surface treatment were determined from relative intensities of Argon, hydroxyl radical (OH), oxygen (O) I emission spectra. The rotational temperature T rot of Ar + H 2 O plasma was determined from OH emission band. The PMMA surfaces before and after plasma treatment were characterized by contact angle and surface free energy measurements, X-ray photoelectrons spectroscopy (XPS), atomic force microscope (AFM) and UV-spectroscopy. The contact angle decreased and surface free energy increased with plasma treatment time. XPS results revealed the oxygen to carbon ratio (O/C) on plasma-treated PMMA surfaces remarkably increased for short treatment time ≤60 s, beyond which it has weakly dependent on treatment time. The carbon C1s peak deconvoluted into four components: C–C, C–C=O, C–O–C and O–C=O bonds and their percentage ratio vary in accordance with plasma treatment time. AFM showed the PMMA surface roughness increases with plasma treatment time. UV-visible measurements revealed that plasma treatment has no considerable effect on the transparency of PMMA samples.

Heterogeneous Bonding of PMMA and Double-Sided Polished Silicon Wafers through H2O Plasma Treatment for Microfluidic Devices

“…The pristine PMMA sample exhibited high transmission in the visible region of the spectrum above 300 nm, about 94% or higher. The optical absorption of PMMA is very small, less than 250−300 nm, and it exhibits higher transmission in the visible wavelength range [52,53]. The substrate produced using the plasma treatment did not differ much from the non-plasma treated samples, having had excellent interfacial adhesion together with excellent light transmittance efficiency.…”

“…Plasma ionization and dissociation of water vapor on the PMMA surface bond hydrogen atoms and OH. These reactions are known to generate radicals due to the discharge of the OH + e bonds [29,53]. However, the surface energy of the OH bond is very strong, and this is one of the factors influencing the bonding of the silicon silanol groups Si−OH to the silicon surface.…”

“…The most important effect of plasma exposure seems to be the formation of a disordered surface structure producing Si−O−Si bonds and the generation of H 3 O + + O on the PMMA surface leading to a chain reaction, for examples see Equations (4) and (5). Increased OH radicals driven by a strong electric field could be responsible for the removal of the oxide layer [44,53]. There is evidence of large charge electrons (e − ) in the plasma oxide formed after H 2 O plasma exposure.…”

Wpływ Działania Plazmy Niskotemperaturowej Na Zmiany Zwilżalności Wybranych Polimerów

“…Aktywacja powierzchni materiałów polimerowych plazmą niskotemperaturową umożliwia wprowadzenie na powierzchnię określonych grup funkcyjnych, które mogą oddziaływać specyficznie z innymi grupami, powodując zmianę hydrofilowości bądź hydrofobowości, swobodnej energii powierzchni, a także zwiększenie powierzchniowej przewodności elektrycznej [3,32].…”

“…Jedną z największych wad związanych z wykorzystaniem plazmy do obróbki powierzchni materiałów jest złożoność procesu, co bezpośrednio przekłada się na trudność w jednoznacznym określeniu wpływu danego czynnika na przebieg procesu modyfikacji oraz kontrolowaniu ilości wytworzonych na powierzchni grup funkcyjnych. Dodatkowo, proces modyfikacji wymaga zastosowania próżni, co zwiększa koszty obróbki [32].…”