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The purpose of this paper is to propose and demonstrate a simple yet accurate optical fibre based sensor capable of performing micron and sub‐micron thickness measurement.

The proposed sensor consists of a multimode plastic probe, three He‐Ne lasers and translation stages along with a silicon photodiode and a lock‐in amplifier to measure the output voltage as the displacement of the sensor is increased.

The system operating with a source wavelength of 633 nm can provide measurements of up to 3 μm with a sensitivity of 0.0054 mV/μm.

The thickness of the sample can be obtained from a linear equation correlating the thickness of the sample to the displacement of the sensor at which the peak output voltage is obtained, or by correlating the thickness of the sample directly to the peak output voltage measured.

This paper aims to address the polymerization of 1-decene by [Emim]Cl/AlCl₃ ionic liquid and the film-forming properties of the product compared with commercially available base stocks.

Experiments were carried out to investigate the influence of [Emim]Cl/AlCl₃ mole ratio, catalyst dosage, reaction temperature, reaction time and water on the polyreaction. Poly alpha-olefin (PAO) is prepared under optimal reaction condition. Film-forming properties of PAO have been compared with those of Group I, Group II and Group III base stocks, which are selected with approximately the same viscosity.

Experimental results show that after a 4-h reaction time, yield of PAO can be higher than 85 per cent and viscosity index can be up to 160 with [Emim] Cl/AlCl₃ mole ratio of 2:1, catalyst dosage of 3 per cent wt. and water content of 20 ppm. A strong influence of water on reaction is observed. With approximately the same viscosity, PAO shows the superiority in film thickness at low-sliding speeds compared with Group I and Group II base stocks. At high temperature, PAO provides a thicker film than other base stocks.

In recent years, there has been considerable interest in ionic liquids. As a novel catalyst, it has so many advantages including low corrosion, low toxicity, low cost and a potentially wide range of properties compared with traditional catalysts. This paper reports the polymerization of 1-decene by [Emim]Cl/AlCl₃ ionic liquid and the study on lubricating properties of PAO compared with mineral base stocks.