1951年英国影片《白衣男子》中，主人公西德尼缝制的见光自洁白色套装让许多观众大开眼界。随着纳米技术的发展，澳大利亚和中国科学家已研制出一种自洁纤维，用它制造的衣料具有见光自洁特性。
但英国《每日邮报》2月11日提醒人们，鉴于自洁纤维缺乏安全性检测，不排除其危害人体、污染环境的可能。
香港理工大学参与研究
这一研究成果刊登在新近一期美国化学学会期刊《材料的化学性质》（Chemistry of Materials）上。澳大利亚莫纳什大学和中国香港理工大学研究人员在文章中说，沾有红酒的自洁毛料经过几分钟光照，红酒污渍开始褪色，晾晒一天之后，酒渍完全消失。
自洁面料就是在普通的面料纤维中加入一层薄薄的纳米二氧化钛。纳米二氧化钛粒径仅为10纳米至50纳米，相当于一根头发粗细的二千五百分之一。这种物质已被添加进各种防晒、护肤等化妆品中，起到增强皮肤吸收的作用。研究人员告诉记者，混合形成的自洁纤维颗粒也非常小，100万个颗粒合起来才相当于针尖大小。
这种纤维颗粒可不断自我更新。它在阳光照射下所产生的颗粒与空气中的氧气发生作用，可以分解和蒸发尘土和污渍，达到清洗目的。相似技术已经用于制造可以自我清洗的窗户。
脏衣服脏床单晒晒即可
研究人员已经用自洁纤维面料缝制了一件衣服。试验发现，在阳光照射下，衣服纤维自我清洁效果不错。研究人员设想人们今后再也不用洗床单、羽绒被、枕头，发现它们脏了只需挂在晾衣绳上晒一晒，就能焕然一新。值得一提的是，这种纤维的自洁方式比传统的化学清洗剂更好，不会破坏衣服的质感。
研究人员预计，5年之后，这种纤维就可用于自我清洁衣服批量生产。（来源：信息时报）
（《材料的化学性质》（Chemistry of Materials），10.1021/cm702661k，Walid A. Daoud, K. Qi）
生物谷推荐原始出处：
ASAP Chem. Mater., ASAP Article, 10.1021/cm702661k
Web Release Date: January 23, 2008
Copyright © 2008 American Chemical Society
Self-Cleaning Keratins
Walid A. Daoud,*† S. K. Leung,‡ W. S. Tung,† J. H. Xin,‡ K. Cheuk,‡ and K. Qi‡
School of Applied Sciences and Engineering, Monash University, Churchill, VIC 3842, Australia, and Nanotechnology Centre, ITC, Hong Kong Polytechnic University, Kowloon, Hong Kong, China
Received September 18, 2007
Revised Manuscript Received December 13, 2007
Keratins, a class of biologically fibrous proteins, are tough and insoluble due to the formation of adjacent peptide bond that allow close alignment of the sulfur-containing amino acid constituent, cysteine, enabling the formation of disulfide bridges, cross-links, that confer rigidity and thermal stability to keratinous materials, which make them an important class of fibrous materials. Keratins are a type of natural protein and the main structural constituents of animal tissues. Keratinous protein fibers such as wool, silk, hemp, and spider silk find numerous applications such as insulation, tires, and strong fibers in addition to textiles.1, 2 Although, protein fibers offer excellent physical and processing properties, as biological materials, they lack the minimally required thermal and chemical resistance and intrinsic reactivity of their constituting polypeptide chains to enable modification or fine-tuning of their properties. They are also subject to photodegradation in presence of UV containing light such as solar and indoor lighting. These special characteristics have hindered further functionalization of proteinic materials and limited their full utilization despite their abundance, practicability and biodegradability. Proteinic fibers, capable of converting incident light to self-cleaning power to decompose its stains, dirt, and harmful microorganisms in a process of photocatalytic purification, are very interesting materials for various applications. In this contribution, self-cleaning keratin fibers have been realized following a bottom-up nanotechnology approach in which anatase nanocrystals of titanium dioxide are formulated and carefully applied to the fibers via a near room temperature sol–gel process in order to maintain their intrinsic properties while conferring self-cleaning properties and self-protection against UV degradation. This may enable wider utilization of these natural fibers. Colloids of anatase titanium dioxide, a highly efficient photocatalyst, have recently been prepared via a near room temperature process.3, 4 This synthetic innovation implies that the application of anatase nanocrystals can be extended to low thermal resistance materials such as biomaterials.5–9 However, due to additional low chemical and thermal resistance and liability to photodegradation of protein fibers, a tailor-made anatase colloid should be devised that suits the target application. It was found that a synthetic formulation of an acidic aqueous colloid of titanium dioxide using hydrochloric acid produces single-phase anatase nanocrystals (4–5 nm), which is applicable to a keratin fiber representative, wool, without affecting its intrinsic properties. Although these functionalized fibers were found to possess excellent self-cleaning and UV-protection properties, these properties may not be stable. TiO2 has high affinity toward hydroxyl and carboxylic groups,7, 10–13 especially the latter. However, keratin fibers contain less than 50% of those functional groups. Therefore, it is necessary for these fibers to undergo a chemical modification to their backbone chains to enable stable bonding with the anatase nanocrystals. Acylation of fibers by acid anhydride allows for enrichment of carboxylic groups. Other functional groups on the amino acid residues such as amino, hydroxyl, phenol and thiol groups are also potent reactive sites.14–18 Following the introduction of additional carboxylic groups into the fiber, the change of the binding ability toward metal ions have been studied.14, 18 Succinic anhydride is a nontoxic and mild acylating agent. On the basis of the observed properties of the modified fibers, it was found that the acylation reaction allows for increasing functionality and reactivity toward anatase nanocrystals which in turn resulted in enhanced self-cleaning functionality. This finding may open up new applications and extendibility to other proteinic materials.
Succinylation of fibers was carried out in DMF at 60 °C as shown in Scheme1. Details of the succinylation reaction are given in the Supporting Information. This reaction introduces additional carboxylic groups to proteinic fibers which are potential reactive functional groups. ATR-IR spectroscopy was applied to verify the reaction of the anhydride with the fibers through the changes in the spectral regions and the characteristic absorptions of the ring-opened anhydride molecules (Figure1). The spectrum of succinylated fiber PS showed spectral changes in the regions 1750–1700 and 1152 cm−1. The band at 1750–1700 cm−1 is ascribed to the carboxylic groups that arise from the opening of the anhydride ring and the spectral absorption at 1152 cm−1 corresponds to the C−O−C stretching which could arise from the formation of ester bonds by the acylation of hydroxyl groups on the amino acid residue. After modification, the fibers were treated with nanosized TiO2 colloid T60 by a dip coating process. Attempts were made to examine the chelating effect between titanium atom and carboxylate groups of modified fibers by ATR-IR technique, however the absorption band at 1530 cm−1 assigned to the coordination of oxygen atoms of carboxylic groups toward titanium atoms11–13 cannot be easily observed in the spectrum of T60-coated modified sample TS because of the overlapping with bands corresponding to other functional groups of the fibers.
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