The Morphology and Mechanical Properties of Polycarbonate/Acrylonitrile Butadiene Styrene Modified by Ar Ion Beam Irradiation Sk. Faruque Ahmed, Jin Woo Yi, Myoung-Woon Moon,* Yong-Jun Jang,* Bong-Hyun Park, Seong-Hoon Lee, Kwang-Ryeol Lee Introduction Polycarbonate and acrylonitrile butadiene styrene (PC/ABS) alloys are well-known commercial polymers. The advan- tage of the PC/ABS combination is that they form blends, where ABS helps to reduce the cost and PC contributes to heat resistance. Due to the appropriate combination of the two components, PC/ABS is widely used in engineering thermoplastics, such as aircraft interior trim, car wind- screens, automobile interior parts, safety helmets, and display screens. [1–3] The major drawbacks of PC/ABS are its low hardness, low scratch resistance and degradation by ultraviolet radiation as well as permeability to gases. In order to overcome these drawbacks, functional coatings applied to the surface of the polymer can provide protection from scratching damage. A thin film coating can improve the mechanical, chemical properties and compatibility of PC/ABS, which are useful in protective optical materials or biomedical products. However, the direct deposition of hard thin film coatings on polymer substrates causes problems with film adhesion. [4–6] From the standpoint of environment protection, plasma technologies play an important role in surface treatment of polymers through use of a low temperature glow discharge, ion beam bombardment. Surface treatments with Ar, N 2 ,O 2 , CF 4 , Ga, CO 2 , and He ions, on a polymer can affect the structural properties, optical properties, electrical conductivity [7–11] as well as the chemical properties, i.e., wettability and biocompatibility for implants. [11–15] The mechanical properties such as the hardness and tribological properties of polymers can be also modified by high-energy, Full Paper Sk. F. Ahmed, J. W. Yi, M.-W. Moon, K.-R. Lee Future Convergence Technology Laboratory, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130- 650, Republic of Korea Fax: þ82 2 958 5509; E-mail: mwmoon@kist.re.kr Y.-J. Jang, B.-H. Park, S.-H. Lee Polymeric Materials Research Team, Research & Development Division for Hyundai Motor Company & Kia Motors Corporation, Gyeonggi-Do, Republic of Korea E-mail: yjjang@hyundai-motor.com This study examined the surface morphological evolution of polycarbonate and acrylonitrile butadiene styrene (PC/ABS) irradiated with an Ar ion beam using an ion beam system. PC was not affected by the Ar ion beam treatment at a lower ion beam treatment times but the ABS portion formed a foam-like nanostructure at the surface. On the other hand, both PC and ABS formed nanostructures with length of 100 to 120 nm and a mean diameter of 35 nm at longer beam treatment times. The Raman and FTIR spectra revealed polymer chain scissioning. Nanoindentation showed that the hardness and elastic modulus of the PC/ABS decreases from 0.22 to 0.18 GPa and from 3.39 to 2.98 GPa, respectively with increasing Ar ion beam treatment time due to the surface nano-structures formed by Ar ion beam. 860 Plasma Process. Polym. 2009, 6, 860–865 ß 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/ppap.200900043