(US5164465-A)      A sulphonated polyaniline compsn. has recurring units of formula (I) where y = 0-1, R1, R2, R3, R4, R5 and R6 are H, -SO3H, R7SO3H, -SO3M, -R7SO3M, -OCH3, -CH3, -C2H5, -F, -Cl, -Br, -I, -N(R7)2, -NHCOR7, -OH, -O-, -SR7, -OR7, -OCOR7, -NO2, -COOH, -COOR7, -COR7, -CHO and -CN, where R7 is 1-8C alkyl, aryl or aralkyl gp., and M is a positive cation. The sulphonated polyaniline compsn. is comprised of x and z fractions of phenyl or quinoid rings, where x is that fraction of phenyl or quinoid rings that have an -SO3- gp. and where z is that fraction that have an -SO3- gp. and the M positive cation, such that when the sulphonated polyaniline compsn. has fewer z fractions than x fractions, the compsn. is a conductor and as the number of z fractions approaches the number of x fractions, the compsn. becomes non-conducting.    USE/ADVANTAGE -   Useful for adsorption of electromagnetic radiation, as a high density erasable data storage medium, and is optical microelectronic devices.    (JP5503953-W)      Compsn. (I) contains a sulphonated polyaniline (II): y = 0-1; R1-6 = H, SO3H, R7SO3H, SO3M, R7SO3M, OCH3, CH3, C2H5, F, Cl, Br, I, N(R7)2, NHCOR7, OH, O-, SR7, OR7, OCOR7, NO2, COOH, COOR7, COR7, CHO or CN; R7 = 1-8C alkyl, aryl or aralkyl; and M = positive cation, pref. Li+, Na+, K+, Rb+, Cs+, NH4+, Ca2+ or Ba2+. Fraction of phenyl or quinoid rings that have an SO3- gp. is x. The fraction of these phenyl or quinoid rings that have M is z. When z is less than x, (I) is a conductor; when the value of z approaches that of x, (I) is non-conducting.    USE/ADVANTAGE -   (I) have claimed uses as an electromagnetic absorbing compsn., optical coupling device, microwave attenuator, erasable optical information storage appts. and a three dimensional holographic grating.    (JP2953671-B2)      Compsn. (I) contains a sulphonated polyaniline (II): y = 0-1; R1-6 = H, SO3H, R7SO3H, SO3M, R7SO3M, OCH3, CH3, C2H5, F, Cl, Br, I, N(R7)2, NHCOR7, OH, O-, SR7, OR7, OCOR7, NO2, COOH, COOR7, COR7, CHO or CN; R7 = 1-8C alkyl, aryl or aralkyl; and M = positive cation, pref. Li+, Na+, K+, Rb+. Cs+, NH4+, Ca2+ or Ba2+. Fraction of phenyl or quinoid rings that have an SO3- gp. is x. The fraction of these phenyl or quinoid rings that have M is z. When z is less than x, (I) is a conductor; when the value of z approaches that of x, (I) is non-conducting.    USE/ADVANTAGE -   (I) has claimed uses as an electromagnetic absorbing compsn., optical coupling device, microwave attenuator, erasable optical information storage aptps. and a three dimensional holographic grating.