## Results
### LP Plasma Deposition of Differently Cell-Repulsive Coatings
The FT-IR spectrum reveals also the stretching band of the CH\({}_{2}\) groups (2940-2810 cm\({}^{-1}\)) and that of carbonyl groups (1723 cm\({}^{-1}\)). By changing the input power from 5 to 50 W (strategy 1 of Figure 1) it is possible to see the decrease in the COC ether contribution at 1100 cm\({}^{-1}\), and the increase in the carbonyl band at 1723 cm\({}^{-1}\). This result could be due to inter-chain crosslinking or to the fragmentation of polymer chains (i.e., the prevalence of short chains). When VAc is used as the monomer, the twisting and wagging of CH\({}_{3}\) groups at 1240 cm\({}^{-1}\) and 1368 cm\({}^{-1}\), respectively; appear in the FT-IR spectra of Figure 3; moreover, the C=O stretching band (1723 cm\({}^{-1}\)), that is the characteristic fingerprint of the VAc structure, decreases as the input power increases from 5 to 50 W. Coatings deposited from the blend of the two monomers (Figure 3b) show the characteristic bands of both monomers, especially at low input power. The C=O stretching peak at 1723 cm\({}^{-1}\) decreases as the input power increases from 5 to 15 W, then it increases again at 50 W.  
Besides the bulk, the surface composition of the coatings is very important for applications, for it is the arena where the interactions between biological entities and material occur and could be engineered to pre-determined effects such as non-fouling or cell-adhesion properties. In Figure 4 the XPS C1s spectra of coatings deposited from DEGDME, VAc, and a mixture of them, at different powers values are reported. The chemical composition of the coatings in terms of PEO-character tightly depends on the DEGDME content in the feed, and the power input delivered to the discharge (Table S1). The PEO-character decreases with the increase in power from 70% to 30% in coatings deposited in discharges fed with only DEGDME (Figure 4a-c), and decreases at least 20%  
Figure 3: FT-IR spectra acquired on coatings deposited from different gas feeds: (**a**) DEGDME (53 Pa, 60 s); (**b**) mixture of VAc/DEGMDE (4.5/0.5 ratio, 53 Pa, 60 s; (**c**) VAc (53 Pa, 60 s). The spectra were acquired for coatings deposited at 5 W (red), 15 W (green), and 50 W (blue). from a pure DEGDME discharge to a process fed with only VAc, at any power delivered to the plasma (compare Figure 4a,g, Figure 4b,h, Figure 4c,i). The coatings deposited from only DEGDME at 50 W are less stable in water than those coatings deposited at 15 W and 5 W (i.e., the PEO-character of DEGDME coatings deposited at 50 W decreases 20% after soaking, Table S1). The water soaking does not allow the complete dissolution of the deposited films as attested by the absence of Ti signal in the acquired low resolution (survey) XPS spectra before and after water immersion (Figure S1). A similar behavior, although not as drastic, is observed also for coatings deposited from VAc/DEGDME mixtures and VAc (i.e., changes of PEO-character up to 10% after water soaking, Table S1). Only variations of oxygen on carbon ratio (O/C) composition were revealed, no titanium from the underlying substrate was detected, so the modifications after soaking in water could be ascribed to leaching of weakly bound fragments rather than to delamination or dissolution of the PE-CVD layer. Coatings deposited from a VAc/DEGDME are less stable in the water when deposited at 5 W, as attested by the increasing of the O/C ratio and of the PEO-character (see Table S1), probably for the low cross-linking degree of the coatings deposited at low power, and presence of polar groups that could contribute to the dissolution of weakly bound fragments. The more stable VAc/DEGDME coatings are the ones deposited at 15 W.  
The results of cell growth after 1 and 5 days on the most stable coatings on titanium substrates are shown in Figure 5. Coatings deposited from DEGDME at 5 and 15 W of power (i.e., DEGDME_5W and DEGDME_15W), from VAc at 5 W and 15 W (i.e., VAc_5W and VAc_15W) and from VAc/DEGDME 4.5/0.5 mixture at 15 W (i.e., VAc/DEGDME_15W) have been investigated.