Liquid thermal pads do not cure like RTV silicones, they remain mushy. If you need adhesive in particular, RTV silicone can be used for that. You need neutral cure silicone to use anywhere near the electronics and most of them emit acetic acid when curing. Permatex appears to be fine. DoneDeal says "Sensor safe when cured" which is very suspicious wording, no datasheet too. Normal RTV silicone can be used as thermal interface if heat dissipation and thickness are not high. Generally you can expect about 0.2-0.3 W/mK thermal conductivity, although some are significantly worse. Don't use it between two wide pieces of metal as it will take forever to cure in the middle. Wide plastics are generally fine as they pass moisture to some extent. If you need high thermal conductivity, there are some special silicones. Do not expect any outstanding thermal conductivity unless there is exact number in the datasheet. If silicone say contains only 10% of copper, it won't improve thermal conductivity too much.