In the field of cosmetics, it is very important to investigate catalytic activities of powders, which may degrade the quality of products, such as foundations, lipsticks, and blushers. Inactivation of the powders is indispensable in the preparation of high quality cosmetics. We have developed a novel method for producing functional powders in a two-step method; (1) chemical vapor deposition (CVD) of tetramethylcyclotetrasiloxane (H-4), and (2) hydrosilylation. After the H-4/CVD process, it was found that the H-4 molecules deposited on powders formed a network structure of polymethylsiloxane (PMS), which seems to have been caused by catalytic activities of the powders, as shown by the following reaction; 2 >Si-H + H₂O → >Si-O-Si< + H₂ The thickness of PMS film on the powder surface was estimated to be less than 1 nm, which corresponds to a mono- or bimolecular layer. In spite of their small thickness, the catalytic activity of PMS-powders was totally eliminated. In the second step, various functional groups could be added to the PMS film by the following reaction; >Si-H + CH₂=CHR → >SiCH₂CH₂R (R: functional group) Introduction of several different functional groups, for example, alkyl, hydroxyl, and quaternary ammonium groups was attempted, and applied to novel powders for cosmetics and novel columns for high performance liquid chromatography.