Scale inhibitors and related controlled release particles

A composition comprising:

• a porous particle;
• a material in pores of the porous particle;
• and
• a coating bonded to a surface of the porous particle,
• wherein the coating comprises a multi-urethane compound capable of reversibly converting between a condensed state and an expanded state upon exposure to a stimuli,
• wherein the multi-urethane compound comprises Compound III and/or Compound IV
• where n=1-12;
• R1═—CH2—CH2—, —CH2—CH2—NH—CH2—CH2—, —CH2—CH2—NH—CH2—CH2—NH—CH2—CH2—, —CH2—CH2—NH—CH2—CH2—NH—CH2—CH2—NH—CH2—CH2—,
• or
• R2=hydrogen or methyl;
• and
• R4=methyl, ethyl, i-propyl, or t-butyl.