The central compound of Silver,s adhesive was an acrylate copolymer. But the adhesive was too weak and wouldn,t stick for long. Acrylate Polymers were a category of chemical compounds often used in paints,plastics and textiles. what Fry wanted was the perfect pressure-sensitive adhesive. He experimented with particles called microspheres,tiny round molecules. when sprayed onto a surface, the adhesive coating was just like the pebbled surface of a basketball. By spraying the adhesive in the from of these round microspheres, he could coat a surface that wasn,t too sticky or too weak. this allowed a post-it note to stick onto the page of a book, but it could later be easily removed and stuck again somewhere else. Conversely, normal packing tape had a flat surface, hence allowing it to stick permanently