A low power 50Hz argon plasma for surface modification of polytetrafluoroethylene

The characteristics of a low power 50 Hz argon plasma for surface treatment of polytetrafluoroethylene(PTFE)film is presented in this article.The current–voltage behavior of the discharge and time-varying intensity of the discharge showed that a DC glow discharge was generated in reversed polarity at every half-cycle.At discharge power between 0.5 and 1 W,the measured electron temperature and density were 2–3 eV and∼10^(8) cm^(−3),respectively.The optical emission spectrum of the argon plasma showed presence of some‘impurity species’such as OH,N_(2) and H,which presumably originated from the residual air in the discharge chamber.On exposure of PTFE films to the argon glow plasma at pressure 120 Pa and discharge power 0.5 to 1 W,the water contact angle reduced by 4%to 20%from the original 114°at pristine condition,which confirms improvement of its surface wettability.The increase in wettability was attributed to incorporation of oxygen-containing functional groups on the treated surface and concomitant reduction in fluorine as revealed by the XPS analysis and increase in surface roughness analyzed from the atomic force micrographs.Ageing upon storage in ambient air showed retention of the induced increase in surface wettability.

Robust, healable and hydrophobically recoverable polydimethylsiloxane based supramolecular material with dual-activate hard segment

In this paper, a novel dual-activate hard segment strategy is proposed for the fabrication of polydimethylsiloxane(PDMS) based supramolecular polymer(PDMS-PDITC-IPDI). The unique design endows the PDMS-PDITC-IPDI with high toughness(43.1–24.5 MJ/m^(3)), tensile strength(11.3–6.6 MPa) and elongation at break(730%–615%), and the mechanical properties and dynamic property can be regulated by varying degrees of hard segment activation. Moreover, the PDMS-PDITC-IPDI polymers exhibit excellent self-recovery property during successive loading-unloading processes. Additionally, both wettability damage caused by O2 plasma treatment and mechanical damage can be healed by simple heating, showing good hydrophobic recovery and selfhealability. Taking advantages of merits of the PDMS-PDITC-IPDI, the applications of the material as recyclable adhesive and 3D printing material are also investigated.