Compositions comprising cleavable crosslinker and methods

A composition is described comprising a polymer. The polymer comprises polymerized units derived from a cleavable crosslinking monomer. The cleavable crosslinking monomer comprises at least two free-radically polymerizable groups and at least one group having the formula -O-C(R2)(R3)-O-, wherein R2 and R3 are independently hydrogen, alkyl, or aryl. The composition has a Tg no greater than 50 DEG C. In some embodiments, the composition has a storage modulus greater than 3 * 105 Pa at 25 DEG C and 1 Hz and may be characterized as a non-tacky polymer. In other embodiments, the composition is a pressure sensitive adhesive. Upon cleavage of at least a portion of the polymerized monomeric units derived from the cleavable crosslinking monomer, the composition exhibits a change in at least one physical property. In another embodiment, the composition comprises a polymer and fragments. The fragments comprise the reaction product of a free-radically polymerizable group bonded to a polymer chain and a pendent hydroxyl g