lps is found in the capsule of gram-negative bacteria
The capsule--which can be found in both gram negative and gram-positive bacteria--is different to the second lipid membrane -- bacterial outer membrane, which contains lipopolysaccharides and lipoproteins and is found only in gram-negative bacteria. When the amorphous viscid secretion (that makes up the capsule) diffuses into the surrounding medium and remains as a loose undemarcated secretion, it is known as slime layer.
Bacterial capsule