Examinations were conducted by the static light scattering method on the aggregation number, shape, and size of molecular assemblies formed in aqueous solution of copolymers of acrylic acid and trimethylvinylsilane with a fluoroalkyl group (R-F) on both terminals (fluorinated silicon oligomers having carboxylic acid groups; R-F-(CH2CH(COOH)(x)-(CH2CHSiMe3)(y)-R-F; R-F = C3F7, C2F5(CF2OCFCF3), C2F5- (CF2OCFCF3)(2); abbreviated hereafter to fluorinated silicon oligomers). Molecular assemblies of the fluorinated silicon oligomers with an R-F group on both terminals were found to have an ellipsoidal shape while those of the silicon oligomers with no R-F were spherical or ellipsoidal in shape. Moreover, molecular assemblies of the fluorinated silicon oligomers were found to change their shape from an ellipsoidal to a spherical one with decreases in the length of the R-F chain and the proportion of CH2CH(SiMe3) segments to CH2CH(COOH) segments or an increase in the number of CH2CH(COOH) segments.