Polymer International Polym Int 57:509–514 (2008) A facile method of shielding from UV damage by polymer photonic crystals Jingxia Wang, 1,2 Jie Liang, 1 Huimeng Wu, 1 Wenfang Yuan, 1 Yongqiang Wen, 1 Yanlin Song 1,2∗ and Lei Jiang 1 1 Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, PR China 2 Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, PR China Abstract BACKGROUND: UV radiation is a potent and ubiquitous carcinogen, which is responsible for most of the skin cancer in the human population. General UV protection materials may produce dangerous degradation products under UV irradiation; therefore, safe, nontoxic and simple UV protection approaches are urgent requirements. RESULTS: A series of photonic crystals with stopband covering the range 200–400 nm have been fabricated which can shield radiation from the whole UV range. Both UV-visible and 1 H NMR results confirm the effective protection from UV light of 254 nm. CONCLUSIONS: A facile method for UV protection has been demonstrated by utilizing the unusual optical properties of photonic crystals that can inhibit light propagation at a given frequency without specific requirement of chemical composition. This approach opens a new way to protect from UV damage using safe materials, which is of great significance for extending the practical applications of photonic crystals.  2007 Society of Chemical Industry Supplementary electronic material for this paper is available in Wiley InterScience at http://www.interscience.wiley.com/jpages/ 0959-8103/suppmat/ Keywords: colloidal crystals; macroporous polymer; polymer photonic crystals; UV protection INTRODUCTION UV radiation is a potent and ubiquitous carcinogen, responsible for most of the skin cancer in the human population. 1–3 DNA is considered as the primary chromophore of UV radiation due to its maximum absorbance at 260 nm, and its dimerization between adjacent pyrimidine bases is the most prevalent photoreaction resulting from UV irradiation. 1–6 If the photoproduct cannot be repaired correctly, it may interfere with DNA replication or transcription, and lead to cessation of cell proliferation. 4–6 Therefore, extensive efforts have been made to develop practical and novel UV protection materials. 7–26 However, traditional organic chemicals generally consist of aromatic groups or related derivatives, 8,11 which may lead to toxic degradation products or potentially harmful chemicals on exposure to sunlight. 10 – 15 While inorganic protection materials are mainly made of TiO 2 nanoparticles 19,25 (10–50 nm), the UV protection efficiency is reduced greatly when saturation adsorption is reached. 10 – 15,26 Therefore, safe, nontoxic and easy UV protection approaches are urgent requirements due to the above limitations of traditional organic or inorganic UV protection chemicals. Photonic crystals (PCs), a name first coined by Yablonovitch 27 and John 28 in 1987, have attracted a lot of attention due to their unusual optical properties originating from their stopband that can inhibit light propagation at a given frequency, 29 – 33 and promising applications of PCs have been extensively demonstrated in many fields. 34 – 52 What is more, PC structures have been widely found in nature. Biro and co-workers 45 – 47 investigated extensively these natural PC structures, which often act as the origin of bright signaling colors and control of thermal energy exchange, 46 especially protecting living cells from harmful UV radiations. 47 That is, PCs demonstrate good UV protection effects just by their specific ∗ Correspondence to: Yanlin Song, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, PR China E-mail: ylsong@iccas.ac.cn Contract/grant sponsor: NSFC; contract/grant number: 50625312; U0634004; 20421101 Contract/grant sponsor: 973 Program; contract/grant number: 2006CB806200; 2006CB932100 Contract/grant sponsor: CNKBRSF; contract/grant number: 2006CB921706 Contract/grant sponsor: Chinese Academy of Sciences (Received 20 January 2007; revised version received 26 March 2007; accepted 3 July 2007) Published online 27 September 2007; DOI: 10.1002/pi.2376  2007 Society of Chemical Industry. Polym Int 0959–8103/2007/$30.00