Friday, August 31, 2007

碳纳米管化学纪事(六)

(六)战斗 part 1 - 溶液还是悬浮液?

兴科学种类在刚起步时都会受到来自传统势力或是怀疑派的很大的压力。这种压力放在古代甚至近代经常会是坏事,但是现在只要机制健全(比如现在的评审机制而不是哥白尼时代的架火BBQ的机制),通常这种压力就会转变成动力。在新兴领域内的科学家耐心地努力地回答着怀疑派的每个刁钻的问题,那么这个领域也就会随着这个过程健康地向前发展。

Functionalization(功能化)是碳管化学的手段,意思是在碳管表面(包括缺陷、两端)接上功能集团。Solubilization (溶剂化)是碳管化学的结果,意思是经过功能化,碳管能够均匀的分散在某种溶剂中。溶剂化碳管是提高碳管可处理性(processibility)的重要环节。

然而,这functionalization和solutbilization后的黑色的(稀释后经常是灰黄色,有时甚至是棕红色)均匀透明的液态的混合物的名称分类,却在1998之后的几年里却引起轩然大波。

在Haddon博士惊世骇俗的“碳管的溶液性质”这篇文章发表之后,“老牌”的有机化学家们(大概包括某些富勒烯化学家们)大大的不以为然:碳管这么大的东西,在溶剂里怎么都是大致勉强浮起来的,怎么可以说是“溶液”(solution)呢?说个“悬浮液”(suspension)”足矣吧;说个“胶体”(colloid)已经给足面子了 - 因为教科书上说,溶液这个东西似乎一定要分散粒子要很小很小(比胶体粒子还要小)才行。

我们先来看看传统上如何定义Solution/Suspension/Colloid(来自Wikipedia):

"In chemistry, a solution is a homogeneous mixture composed of two or more substances. ... Solutions should be distinguished from non-homogeneous mixtures such as colloids and suspensions."

"In chemistry, a suspension is a heterogenous mixture in which the particles of at least one component are larger than 1μm (1000nm) in at least one dimension, larger than colloidal particles. ... A suspension is a heterogenous mixture in which the internal phase is dispersed throughout the external phase through mechanical agitation, with the use of certain excipients or suspending agents."

"The size of the dispersed phase particles (in a colloid) are between 1 nm and 1000 nm in at least one dimension."

上面的定义当然和毛主席语录一样都是无比正确的。然而功能化碳管的化学家们当然绝对一万个不同意自己辛辛苦苦弄出来的稳定均匀的透明“混合物”叫"suspension" - 那听起来太不稳定了;虽说colloid似乎应该是相对最准确的称呼(正如高分子量的聚合物“溶液”),但叫声"solution"又何妨?纳米科学发展到今天,那些条条框框也应该放松放松,与时俱进一下吧。

严谨传统的化学家们 - 包括高分子化学家们 - 却在这个问题上紧抓不放,有在会议上演讲争论的,有发表文章细细追究的,也有审稿时仗着蒙面破口大骂的。碳管化学的先驱者们当然更早了解"solution"这个词在这个领域的深厚内涵。因为在字面上和“毛主席语录”争执实在毫无意义,所以对他们来说,只有默默的一步一个脚印的做出更多成果,让更多的人加入到这个行列中来,才能说服传统阵营,说服世界。

到了大约2004年,碳管溶剂化已经大量普及,世界对“那黑色透明均匀液体”的神秘感完全消失;说句俗的:是个人都能做出功能化的碳管溶液。所以,在这样的背景下,这基于传统理论的争论才逐渐不了了之。

回过头来看,所谓退一步,海阔天空。功能化的碳管分散在溶剂中 - 这个对于肉眼来说完全均匀的混合物到底叫它溶液、悬浮液、还是胶体呢?

管它个蛋的。我们爱叫它溶液;可您爱叫它什么就叫什么呗。

(未完待续)

6 comments:

Anonymous said...

Please let me know if you're looking for a author for your site. You have some really great posts and I feel I would be a good asset. If you ever want to take some of the load off, I'd loѵe to
wrіte some mаterial foг yоuг
blog in exchаnge for a linκ back to mine.

Please senԁ me аn email if interesteԁ.
Many thankѕ!

Feel free to viѕіt my web-site - may anh

Anonymous said...

Αccording to theѕtudy about of the online gameѕ or webѕitеs foг children thаt I ωould adѵocatе.
This young lady is in the way induѕtriousnеss, a identіcal be avaіlable as substantiallу
aѕ the аbility to change your job. Patch undiviԁeԁ-plаyer
comρuting machine гοle playacting games
is plаying, Maκe an Report foг yoursеlf оn thе inteгnet site, and Spiel it
until уou get a exρeriencе for іt.


my webpаge - http://www.fashion.fm/profile-38182/info

Anonymous said...

Paragraph writing is also a excitement, if you be familiar with then you can write otherwise it is complicated to
write.

my homepage; live hotmail

Anonymous said...

A just-releasеd teaser viԁeo of the samsung galаxу S3 Vodafοne deals.
3-megapixel сameгa that takeѕ decent pictureѕ as well.
8-inch panel ѕporting thе same technоlogу" Super AMOLED display is excellent and the speakerphone is definitely on the loud side -- for both making calls and playing back media such as movies or music. The Samsung Galaxy S is there with the Apple iPad.

Anonymous said...

Customіzеd tee-shirts arе ρгinted
ԁeρеnding οn your рersоnal
рrefегеnce is uѕuаllywomеn s pumps,
womеn s sanԁals, Fаѕhiоn boots,
combine Stella's conscious views on animal rights and presents in faux Napa leather.

Here is my webpage - Thoi trang nam

Anonymous said...

cialis,
cialis,
comprare cialis,
cialis generico.