c*****e
发帖数: 238 | 1 I read one paper by Fridrickson and Leibler on theory of block copolymer solution
my advisor also mentioned that Matsen Schick has done comprehensive studies on
this, but I did not bother to find them yet.
THe thing is that in the solution, there are 3 different two body interactions
thus \chi*N can not be the key factor. |
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c*****e
发帖数: 238 | 2 From scaling theory, this should be determined by the interaction between
polymer segments and solvent as well as on the concentration of the polymer. |
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w******r
发帖数: 43 | 3 The free energy of block copolymer cosists of three parts:
stretching of core-forming block, stretching of corona-forming block and
surface interaction between core-domain and corona domain/solvent.
Bates once reported the correlation between stretching coefficient of
core-forming block and area perchain.
solution
on
interactions |
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z**h
发帖数: 224 | 4 some say yes, some say no. |
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c*s
发帖数: 2145 | 5 can you control the polydispersity index of your alumina or metal particles <1
.10 before talking about building crystal from micelle? :)
想
？ |
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y***e
发帖数: 6082 | 6 这不是我国内老板做的么？实在不懂，啥意思啊，一个fusion发在angew，一个fission
发jacs
fusion, fission |
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s****e
发帖数: 2934 | 7 ☆─────────────────────────────────────☆
cds (红毛呼呼猪) 于 (Sun Oct 1 23:40:38 2006) 提到:
thanks a lot. BUt my case is kinda special. it is PEG-PtBA, as u know, PtBA
can be dissolved in almost all solvents except water. therefore, the
solubility property of the block polymer is quite similar to homopolymer.
what I am trying to do is to precipitate PEG in MeOH using ether, while
keeping the block polymer micelles in MeOH. This looks viable but I am not
sure this is the best combination or not in |
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s****e
发帖数: 2934 | 8 溶解估计是个问题，做这个实验要准备不同浓度的样品来试。如果分子量大的话要用比较低的浓度，比如50nm的micelle有时用0.1％。你用的浓度是多少?你的base line的data小于10吗？小于10表明你的sample的浓度合适了。眼睛能看见大概要500nm吧？能不能用AFM和TEM？ |
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f*******6
发帖数: 665 | 9 I used 0.002mg/ml solution and still can not get reproducible results.
I am thinking is that possible this technology is not suitibale for long-
chain polymer?
We want to know the size distribution,it is better to stay away microscorpy
比较低的浓度，比如50nm的micelle有时用0.1％。你用的浓度是多少?你的base line的
data小于10吗？小于10表明你的sample的浓度合适了。眼睛能看见大概要500nm吧？能
不能用AFM和TEM？ |
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d****n
发帖数: 237 | 10 for suspension reactions, the particle size ought to be large enough to
filter after the solidification.
are you sure yours is suspension? is it emulsion? |
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o*******r
发帖数: 30 | 11 加入高价电解质试试，或者将pH调到极端值
papers
I |
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r******0
发帖数: 2753 | 12 slow down the stirring. The major difference between emulsion polymierzation
and suspension polymerization is the initiator. One is water soluble, the
other is oil soluble. If you want to get bigger suspension particles, slow
down the stirring might be helpful. |
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h**j
发帖数: 24 | 13 What is the problem with filtration? You can't get the suspension through or
you can get it through but nothing left. When my particle is < 5 micron, it
is very hard to get the suspension through filter paper, but 10 micron I
have no problem. By the way, I use Tyvek 1 micron filter paper. What kind
are you using?
any
? |
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m******k
发帖数: 447 | 14 The problem is that I need to control the particle size around 10 microns
and cannot slow down the stirring.
polymierzation |
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m******k
发帖数: 447 | 15 I cannot get the suspension through the fritted Buchner funnel although it's
the coarse size.
or
it |
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r******0
发帖数: 2753 | 16 Then centrifuge instead of filtration. |
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c*****e
发帖数: 238 | 17 yes, the microscopic size is smaller, but still a micellar solution.
cmc is like a critical point. |
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b*******n
发帖数: 29 | 18 In concentrated surfactant-water mixtures, self-assembled liquid crystalline
structures are formed. |
|
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p******4
发帖数: 38 | 20 As I remember, it depends on the micellar size and density.
If the particles are so small (such as d<100 nm), the whole system is
lightly blue to eyes. If the particles are bigger (such as d>100 nm), the
system looks milky white.
If the dispersant is very concentrated, micelle aggregation happens and it
looks white. If it is diluted, the color will be fainter. |
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s**i
发帖数: 6 | 21 多谢各位的热心帮助。请问能否列一两本关于水包油micells 的书或文献？先谢谢了。 |
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c*s
发帖数: 2145 | 22 got it. the first block is acrylate species and the second block contains
sulphonate group. two samples with different hydrophilic-hydrophobic lengths
were prepared and they self-assembled in water to form micelles, with
either spherical or fiber morphology. |
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c*s
发帖数: 2145 | 23 那看看能不能做成两段以后纯化之了，选择一个PS的良溶剂而不容PCL的，两段形成
MICELLE
有些 |
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S*****n
发帖数: 6055 | 24 各位老大，请教个问题
俺想做个PS-PBD的胶束，选择用hexane做溶剂，希望能弄点胶束出来玩。现在尝试了两
种block copolymer，一个diblock，一个SBS，其中PS的含量都在20-25%，但是发现，
polymer都无法溶解，只能溶胀。。。
想请教一下，如何能实现我的目标呢？
现在有两个想法，一个是继续降低PS的含量，不知道有没有可能溶解？hexane应该是PS
的不良溶剂，但是可以溶解PBD
再一个是再找个PS的良溶剂，跟hexane混起来溶解copolymer，然后把另外一种溶剂除
掉，看看能不能得到PS-PBD的胶束。但是这另外一种溶剂选什么合适，还在琢磨。。。
三年来，除了这个版面，没有看过跟polymer有关的任何东西，都快忘光了。。。问题
比较弱，大家多排砖，多谢！ |
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S*****n
发帖数: 6055 | 25 我的实验要求最后形成在纯hexane里面的分散体系
请问THF如何除去比较好？
多谢！
某一 |
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t***u
发帖数: 20182 | 26 我从来没做过啊。找个篇文献，应该可以找到更多的。hexane boiling point 69oC,
THF 66, 不知道
能不能行。
n-Alkanes (heptane, octane, decane, and dodecane), N,N1-dimethylformamide,
N,N1-dimethylacetamide, and methyl ethyl ketone used
as selective solvents for the block copolymers were of AnalaR grade.
The micellar solutions were prepared by using tetrahydrofuran un-
I less stated otherwise. The block copolymers were first dissolved in
small amounts of tetrahydrofuran to which the selective solvent was
I subsequently added. Tetrahyd |
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t***u
发帖数: 20182 | 29 good idea ah, use water? |
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c*s
发帖数: 2145 | 30 whatever solvent, but Hexane should be outside, the polymer can be dissolved
in DMF for example |
|
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c*******e
发帖数: 178 | 32 敢不敢冒险加加热，不知道你PS的玻璃化温度是多少？嘿嘿，出了事别找我啊。
PS |
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r******0
发帖数: 2753 | 33 If hexadecane can be used to replace hexane, it will be much easier. You may
only need to raise the temperature. |
|
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z*****7
发帖数: 133 | 35 SBS工业上好像是用cyclohexane之类的聚的，实验室好像也有用benzene聚的。 |
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c***i
发帖数: 278 | 36 micelle 除了cryo－TEM，就没有办法看形貌了吗？ |
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c********x
发帖数: 232 | 37 You can always use small angle scattering to back-analyze the morphology of
micelles! |
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b******0
发帖数: 45 | 38 transparent completely? Not cloudy or some light blue?
The solution should not be transparent completely, if it is difficult to
pass 0.45um filter. And it should not be due to high molecular weight. At least, PS of 500,000g/mol can pass through the filter smoothly. It is possible that
there are some micelles formed in the THF solution due to the solubility
issue.
By the way, you should not use larger size filter, or else you may clog the
column. Try other GPC, toluene or DMF. |
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h*****1
发帖数: 26 | 39 大家好:
现在在做湍流减阻的试验用到了氧化胺表面活性剂。由于对氧化胺了解不深遇到了一些
问题。请大家帮忙共同探讨，解决一下。
1. 我们的得到的样品名称是：amine oxide, (C18)， 30wt% . 我想确定一下是不是分
子式和octadecyldimethylamine oxide 一样呢？
2. 我们在110度做湍流试验的时候发现，注入500ppm 氧化胺水溶液， 湍流减阻的效果
很快就不见了（一般情况下只有棒状的表面活性剂在溶液中才有湍流的效果），我认为
是氧化胺在这个温度下结构发生了变化，查了一些资料发现，氧化胺在150-200度之间
才能发生消去反应。应该不是消去反应，各位认为是什么原因呢？
3. 表面活性剂像氧化胺这样的，如何判断它形成的micelle 的形状？可以直接查到吗
？
4 对于温度对表面活性剂水溶液影响的相图在哪里能找到？ |
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j*********6
发帖数: 371 | 41
我用GPC主要是看micelle在水中是否水解。我的两性高分子是不带电的，以前也有人跟
我提过为什么我们的DMF不加LiBr？是不是加盐的作用就是中和poly electrolyte？
谢谢 |
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m*****e
发帖数: 1506 | 42 micelle水解否怎样用GPC来表征？实在不解 |
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a*****a
发帖数: 210 | 43 GPC measures hydrodynamic volume. Molecule chain was confined in micelle. It
makes sense that 略小于起始分子量 if your 起始分子量 means molecular weight
measured in good solvent. Be very careful with water especially when
silicon column was used. Water damages silicon column and gives bad results.
Phenol column is not sensitive to water.
LiBr is necessary if your molecule has strong polar group such as acid, 两性
高分子 no mater it 带电 or not. LiBr will interrupt intramolecular force
since your standard (PS, PMMA)... 阅读全帖 |
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z*******o
发帖数: 136 | 44 去年这个时候合成的，上次使用大概是5个月前，ＧＰＣ检测还是窄分布的。今天发现
峰变宽了并且出现了ＰＥＧ分子量大小的小峰了。
样品是储存在小瓶子里，也没有通惰性气体。 5个月前是好的，现在莫民奇妙变了，觉
得非常奇怪。同时检测了另外一个瓶子里备份用的样品，同样也变质了。。。。
这东西我上次形成micelle 后一个月都没水解的。 现在反而polymer 样品分解了。
不知道大家有没有碰到类似的情况？ |
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z*******o
发帖数: 136 | 45 看到一篇paper 用 Brookheaven BI9000AT system 的DLS 测散射光强，然后说正比于
粒子数目，可以这么测吗？我现在用的这台malvern的DLS测不出来啊。
请问还有什么仪器可以测纳米粒子的数目？ |
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z*******o
发帖数: 136 | 46 来自主题: Macromolecules版 - 画图请教 请问用什么软件可以画出大概类似这样的micelle图来？ 这篇paper里说是用Autodesk
3ds Max，不知道这个软件容易上手吗？谢谢 |
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c*****z
发帖数: 71 | 47 才完成PhD,正要开始Postdoc,在这里向各位大牛求审稿机会
我比较熟悉的方向有Polymer chemistry, block copolymer, stimuli-responsive
polymer, micelles and hydrogels
需要更多信息请PM我，多谢多谢 |
|
发帖数: 1 | 48 化学/高分子/材料 求推荐审稿机会
才完成PhD,准备开始申请绿卡,在这里向各位大牛求审稿机会
涉及的领域主要有polymer/macromoleculear chemistry, self-assembly, drug
delivery, organic electronic materials, hybrid materials, block copolymer,
stimuli-responsive polymer, micelles and hydrogels等
email:[email protected]
如需要更多信息（比如CV或者publication list）请email我，多谢多谢 |
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w********g
发帖数: 186 | 49 汗死....
其实选择性这个东西真的很有趣
我最近可能找我们这边有没有人作simulation看一下那几个polymer的空间结构
还有在溶液里面可能的结构
如果我们看这几个polymer
no hydrophilic groups而且,主要都是片状结构
那么肯定不能像SDS那样行程micelle去做包裹
而且如果参考Arnold的那篇用sodium cholate做gradient centrifugation的那篇
SC的结构,对于其hydrophobic部分
也是这样的一个片状结构
而且也是对高chiral angle的管子有更好的选择性
应该可以告诉我们一些什么东西
我觉得如果有谁能观察到或者模拟出来具体是怎么样wrap在CNT上面
应该会是很好的突破口 |
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z*******o
发帖数: 136 | 50 看到一篇paper 用 Brookheaven BI9000AT system 的DLS 测散射光强，然后说正比于
粒子数目，可以这么测吗？我现在用的这台malvern的DLS测不出来啊。
请问还有什么仪器可以测纳米粒子的数目？ |
|
