pH-Dependent Friction of Polyacrylamide Hydrogels - Allison L. Chau; Conor D. Pugsley; Madeleine E. Miyamoto; Yongkui Tang; Claus D. Eisenbach; Thomas E. Mates; Craig J. Hawker; Megan T. Valentine; Angela A. Pitenis (Tribology Letters, 2023)