Fiber-matrix interface reinforcement using Atomic Layer Deposition

The interface between a matrix and its reinforcement is critical to the final composite properties. There are different ways to enhance bonding between the reinforcing fiber and the matrix, based mainly on surface plasma treatments which usually decrease the fiber tensile strength. In this research, atomic layer deposition (ALD) was tested as a possible way to enhance the chemical bonding between the fiber and matrix in the hope that it would not effect the fiber tensile strength. Microbond tests were carried out to measure the effect of an ALD aluminum oxide (Al₂O₃) coating on the fiber/matrix interfacial shear strength, and the fiber tensile strength was measured in order to assess whether this treatment harms the fiber strength. The ultrahigh molecular weight polyethylene (UHMWPE) fibers that were coated by ALD with aluminum oxide (Al₂O₃) showed a significant increase in the interfacial shear strength without reducing the fibers' ultimate tensile strength.