Fabrication of gold nanostructure decorated polystyrene hybrid nanosystems via poly(L-DOPA) and their applications in surface-enhanced Raman Spectroscopy (SERS), and catalytic activity

Noble metallic nanostructure decorated-polymer hybrid systems provide certain advantages and represent remarkable performances in many applications including surface-enhanced Raman spectroscopy (SERS), catalysis, and biosensing. However, despite numerous attempts to fabricate these hybrid platforms, novel, simple, low-cost, reducing agent-free, and easy-to-follow procedures with significantly well-controlled over the desired nanostructure size are still highly required to prepare these efficient nanosystems. In this study, we propose the fabrication of the gold nanostructure decorated polystyrene (PS) nanospheres (NSs) via the polymer of 3,4dihydroxyphenyl-L-alanine (PLDOPA). For the fabrication of PLDOPA coated PS NSs (PS@PLDOPA), a conformal thin film of PLDOPA was deposited onto the PS NSs by oxidative polymerization. The size, morphology, and interparticle distance of gold nanostructure decorated PS@PLDOPA colloidal composite system (PS@PLDOPA@Au NP) was manipulated by simply tuning the amount of the gold ions. The optimized PS@PLDOPA@Au NP systems showed extraordinary characteristics in SERS with an enhancement factor of 4.3 x 105 and catalytic activity in the total conversion of 4-nitrophenol within 5 min