TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The conversion of sulfonic acid or sulfonic ester groups is done in the presence of alkaline hydroxide, preferably sodium hydroxide. The oxidant is ferric chloride.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The process is carried out in a dispersant from water and/or polar organic solvent. Preferred Component: The oxidant is iron (III) salt, or iron(III)tosylate.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The particle contains sterically protruding neutral groups and/or an excess of anionic functional groups covalently bonded to its core surface. The core consists of a synthetic organic polymer which is crystalline or amorphous at 20 degrees C and having a glass transition temperature of not greater than 150 degrees C, preferably from olefinic polymers. The core consists of polystyrene (preferably) or polyacrylics. The anionic functional group is carboxylate, sulfonate and/or phosphonate groups, preferably sulfonate and/or phosphonate groups, which are present as polyanionic chains obtainable by co-oligomerization or polymerization of the core particle with PG-Sp-Ra'monomers, preferably vinylbenzenesulfonic, 2-8C alkenylsulfonic, (meth)acryloyloxy-2-8C alkyl-sulfonic, (meth)acryloylamido-2-8C alkyl-sulfonic, vinylbenzenephosphonic, 2-8C alkenylphosphonic, (meth)acryloyloxy-2-8C alkyl-phosphonic, or (meth)acryloylamido-2-8C alkyl-phosphonic acids or its esters or salts. The oxidatively polymerized shell is obtained by oxidative coupling of optionally substituted pyrrole (preferably), aniline or thiophene. The anionic groups are located on oligomeric or polymeric hydrocarbon chains of 8-100C atoms.PG=polymerizable group like a vinyl group;Ra'=anionic functional group;andSp=direct bond or organic spacer comprising 1-50C from alkylene, cycloalkylene and/or arylene (optionally substituted with O, S or N, preferably O and/or S).Preferred Process: The layered particle is prepared by copolymerizing a monomer containing functional groups SO3H, SO3M or SO3R1, optionally converting SO3H and SO3R1 if present to SO3M, (preferably SO3Na), and polymerizing pyrrole on the surface of the particles. The polymerization is done by adding 1H-pyrrole and an oxidant.M=one metal cation;andR1=1-20C hydrocarbon residue from 1-8C alkyl with styrene sulfonic acid or its salt or ester. EXAMPLE - A mixture (g) of styrene (7.84), divinylbenzene (0.2) and sodium dodecylsulfate (2.5), was added with 4-vinylbenzoic acid sodium salt (160 mg) and water (250 ml), purged with nitrogen for 15 minutes, added with 1-pentanol (1.75 g), homogenized at a speed of 300 room in the presence of nitrogen for 1 hour, heated in an oil bath at 90 degrees C, added with potassium peroxodisulfate (0.2 g) and water (10 ml), polymerized at 90 degrees C for 6 hours, cooled to room temperature, and filtered to obtain particles with a diameter of 12.8 nm.