Melt growth of tetrahydrofuran clathrate hydrate and its inhibition: method and first results

Tetrahydrofuran clathrate hydrate single crystals grow from the supercooled melt as octahedra, showing that {1 1 1} is the slowest-growing face. The addition of poly(vinylpyrrolidone), poly(vinylcaprolactam) or a random terpolymer of the previous two with dimethylaminoethylmethacrylate causes the crystals to grow as hexagonal plates also bounded by {1 1 1} faces. Plate thickness decreases with increasing concentration of the impurity, until growth is altogether inhibited at a concentration of polymer that depends on supercooling.