A method for preparing a lubricity coating on a plastic substrate, in which the substrate is a syringe, the method comprising: (a) providing a gas consisting of: i. an organosilicon precursor, ii. oxygen, and iii. a diluent gas, optionally a noble gas, for example argon, helium, krypton, xenon, neon, or a combination of two or more of these diluent gases in the vicinity of the substrate surface; and (b) generating plasma in the gas by providing plasma-forming energy adjacent to the plastic substrate, thus forming a coating on the substrate surface by plasma enhanced chemical vapor deposition (PECVD); in which: • the gas comprises from 1 to 6 standard volumes of the organosilicon precursor, from 1 to 100 standard volumes of the diluent gas, and from 0.1 to 2 standard volumes of O 2; • the plasma-forming energy is applied in a first phase as a first pulse at a first energy level followed by further treatment in a second phase at a second energy level lower than the first energy level, and reduces the breakout force, Fi, of the syringe, compared to the breakout force of a similar syringe that has only been treated at the second energy level; • the resulting lubricity coating has the composition Si w O x C y H z or Si w x C y H z wherein w is 1 as measured by X-ray photoelectron spectroscopy, x is from about 0.5 to about 2.4 as measured by XPS, y is from about 0.6 to about 3 as measured by XPS, and z is from 2 to about 9 as measured by Rutherford backscattering spectrometry; and • the lubricity coating has a lower frictional resistance than the uncoated surface. (a) providing a gas consisting of: i. an organosilicon precursor, ii. oxygen, and iii. a diluent gas, optionally a noble gas, for example argon, helium, krypton, xenon, neon, or a combination of two or more of these diluent gases in the vicinity of the substrate surface; and i. an organosilicon precursor, ii. oxygen, and iii. a diluent gas, optionally a noble gas, for example argon, helium, krypton, xenon, neon, or a combination of two or more of these diluent gases in the vicinity of the substrate surface; and (b) generating plasma in the gas by providing plasma-forming energy adjacent to the plastic substrate, thus forming a coating on the substrate surface by plasma enhanced chemical vapor deposition (PECVD); • the gas comprises from 1 to 6 standard volumes of the organosilicon precursor, from 1 to 100 standard volumes of the diluent gas, and from 0.1 to 2 standard volumes of O 2; • the plasma-forming energy is applied in a first phase as a first pulse at a first energy level followed by further treatment in a second phase at a second energy level lower than the first energy level, and reduces the breakout force, Fi, of the syringe, compared to the breakout force of a similar syringe that has only been treated at the second energy level; • the resulting lubricity coating has the composition Si w O x C y H z or Si w x C y H z wherein w is 1 as measured by X-ray photoelectron spectroscopy, x is from about 0.5 to about 2.4 as measured by XPS, y is from about 0.6 to about 3 as measured by XPS, and z is from 2 to about 9 as measured by Rutherford backscattering spectrometry; and • the lubricity coating has a lower frictional resistance than the uncoated surface.