Compositions include a compound preparable by reaction of components comprising an optionally crosslinked polyethylenimine and at least one an amine-reactive hydrolyzable organosilane represented by the formula R—Z—SiY3. R represents an amine-reactive group containing 1 to 18 carbon atoms; Z represents a divalent organic group containing 1 to 8 carbon atoms; and each Y independently represents a hydrolyzable group. Methods of using the compositions to make articles, and articles produces thereby are also disclosed. A composition comprising an intimate mixture of a crosslinked polyethylenimine and a polymeric binder material, and a method of making it is also disclosed.