Hydrolysis of HMT forms the protona

Hydrolysis of HMT forms the protonated species
(CH2)6N4H+, which is expected to be adsorbed on the negatively
charged gum arabic. However, because of the very
low isoelectric point of gum arabic, it is still basically negatively
charged to initiate the double-layered Zinc nitrate hydroxide
hydrate phase. Then local protonated HMT was
able to undergo further hydrolysis to generate hydroxide
before growth of ZnO according to the shown reactions.
Our proposed mechanism for the physical process of formation
of the twin-brush ZnO mesocrystals is shown in
Scheme 1. In solution, Zn ions (Scheme 1 a) reacted with hydroxyl
ions which originated from thermal decomposition of
HMT[47] to form two kinds of intermediate nanoparticles
with a size ranging from 3 to 5 nm. The major one is zinc nitrate
hydroxide hydrate Zn5ACHTUNGTRENUNG(NO3)2(OH)8·2H2O) and the
minor one is zinc hydroxide Zn(OH)2 (Scheme 1 b). Then,
mediated by gum arabic, the nanoparticles aggregate together
to form nanoplates with a uneven surface and thickness
of about 10 nm (Scheme 1 c). Polymer-mediated aggregation
of ZnO has been observed previously under hydrothermal
conditions.[48] During the process, these nanoplates self-adjusted
their orientations to form well-ordered crystalline
nanoplates before phase transformation.
After that, the surface of double-layered nanoplates with
the size about 200 nm in diameter underwent surface recrystallization
(Scheme 1 e). Because of the long-range intrinsic
dipole field of ZnO nanoplates, two nanoplates with opposite
dipolar directions connect together to cancel out the
electric field of whole double-layered nanoplate by utilizing
negatively charged gum arabic as a mediating layer. During
this stage, the nanoplates would adjust their orientation by
small mineral bridges between two opposite parts of the
double-layer plate. In addition, Zn5ACHTUNGTRENUNG(NO3)2(OH)8·2H2O with
dipolar characteristic would stack on both surfaces of the
double nanoplates before undergoing a phase transformation
(Scheme 1 d). At the same time, while the nanoplates
were almost all converted to ZnO, nanorods would form on
the layered nanoplates. Thus, the size and thickness of multilayered
nanoplates increased rapidly, and the surface morphology
of both sides of mesocrystals also changes from flat
to concave (Scheme 1 f). The multilayered ZnO nanoplates
on the whole mesocrystal still kept their preferential orientation
due to the small bridges connecting them. The edges
of the concave surfaces on both sides of mesocrystals would
provide a growth site to attract amorphous intermediates,
followed by formation of ZnO nanorods on both sides
(Scheme 1 g). Finally, the twin-brush ZnO mesocrystals were
obtained.
Finally, we make some comparisons with existing works
and summarize the impact of the reaction conditions on the
morphology. First, in our mechanism the growing ends of
the twin crystals are negatively
charged due to the O-terminated
surface of the (0001) plane,
which is less protected, as was
found in other similar reported
cases of ZnO twin crystals with
organic anions as the additive.
Cho et al. recently obtained a
twin crystal form of ZnO using
ascorbic acid as an additive.[49]
However, their structures
tended to be polycrystalline
and nonporous instead of
single-crystal-like and porous.
Apparently, the less diffusive
polymer gum arabic would mediate
better oriented attachment
and stay in the mesocrystal rather than moving out of
it. Generally, polyelectrolyte-encapsulated inorganic nanocrystals
could orientedly attach to each other better because
they have a longer time to search for the best epitaxial fit
and fusion. In our previous work on preparing twin-plate
forms of ZnO, gelatin was used. Gelatin has both carboxylate
groups and positively charged amine groups. Thus, both
of the polar planes (O- and Zn-terminated faces) are
adsorbACHTUNGTRENUNGed by gelatin. Growth in the c direction is thus more
inhibited and results in the twin-plate form. Gum arabic is
an interesting intermediate case; it is a mixture of saccharides
and glycoproteins showing excellent properties as a
glue and binder to many different surfaces. Although it is
highly negatively charged at neutral pH (Supporting Information
Figure S5), there are still some amine groups to protect
the growing O-terminated surfaces of the twin brush
somewhat. Initially, the growth was thus still in plate form.
However, when the pH value drops at a later stage the Oterminated
surface becomes less protected and at the same
time the dipole field originating at the center becomes
stronger to guide the growth to a nanorod form and bend
along the field direction (Scheme 2) to a final vertical direction.
When strong simple electrolytes are added, the dipole
field is greatly screened and the structure reverts to a twin-
Scheme 1. Schematic of the formation mechanism of twin-brush ZnO mesocrystals.
Chem. Eur. J. 2012, 18, 16104 – 16113  2012 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim w

結果 (繁體中文) 1:

HMT 水解形成質子化物種(CH2) 6N4H +，預計將會吸附在消極阿拉伯樹膠帶電。然而，由於的很阿拉伯樹膠的低等電點，它是仍然基本上消極負責啟動雙層鋅硝酸氫氧化水合物相。HMT 當時當地的質子化能夠接受進一步水解生成氫氧化前圖所示的反應氧化鋅的增長。我們建議的機制形成的物理過程雙刷氧化鋅 mesocrystals 中所示方案 1。在解決方案中，鋅離子 (方案 1) 與羥基反應這源于熱分解的離子HMT [47]，形成兩種中間納米粒子具有大小從 3 到 5 毫微米。其中主要是鋅、 硝酸鋅氫氧化水合物 Zn5ACHTUNGTRENUNG(NO3)2(OH)8·2H2O) 和未成年人是鋅氫氧化鋅 (OH) 2 (計畫 1 b)。然後，介導阿拉伯樹膠，納米粒子聚合在一起向表單納米厚度與路面不平約 10 nm （1 c 計畫）。聚合物介導的聚合氧化鋅下觀察了以前熱液條件。[48] 在過程中，這些納米自我調整其形成有序取向結晶前相變納米。在那之後，與雙層納米表面大小約 200 毫微米直徑經歷了表面的再結晶(方案 1 e)。由於遠端內在偶極子場的對面有兩個納米 ZnO 納米偶極方向連接在一起以抵消通過利用整個雙層奈米的電場作為一個仲介層帶負電阿拉伯樹膠。期間這個階段，納米將調整其方向由小礦物橋之間的兩個相反部分雙電層板。此外，Zn5ACHTUNGTRENUNG (NO3) 2 (OH) 8·2H2O 與偶極特性將堆疊上的兩面在接受相變前雙納米（方案 1 d）。在相同的時間，同時納米幾乎都是轉換為氧化鋅，納米棒會形成上層狀的納米。因此，大小和厚度與多層迅速增加，納米和表面形貌雙方的 mesocrystals 也會更改從平凹 （方案 1 f）。多層的氧化鋅納米mesocrystal 整體上仍保持其擇優取向由於小橋樑連接它們。邊緣mesocrystals 兩側的凹曲面會提供一個增長網站吸引非晶的中間體，雙方隨後形成的氧化鋅納米棒（方案 1 g）。最後，雙刷 ZnO mesocrystals 了獲得。最後，我們用一些比較現有作品與總結反應條件的影響形態特徵。首先，在我們成長的兩端的機制孿晶消極地是由於 O 終止被控表面的 (000 1) 飛機，這是不受保護，正如發現在其他類似的報導氧化鋅雙晶體的情況下作為添加劑的有機陰離子。最近獲得的 Cho 等人氧化鋅使用雙晶型抗壞血酸作為一種添加劑。[49]然而，他們的結構傾向于多晶矽和無孔而不是單水晶般和多孔。顯然，不擴散阿拉伯樹膠聚合物會調解更好地面向的附件留在 mesocrystal，而不是移動的它。一般來說，聚電解質封裝無機納米晶可以減弱將附加到彼此更好因為他們有更長的時間來搜索最好的外延適合與融合。在我們以前的工作，準備雙板上採用氧化鋅，明膠的形式。明膠具有兩個羧酸組和正電荷的胺組。因此，兩個（O 和鋅終止面臨） 極地飛機的adsorbACHTUNGTRENUNGed 由明膠。C 方向增長因而是更多抑制和雙板形式的結果。阿拉伯樹膠是一個有趣的中間案例;它是糖的混合物和糖蛋白表現出優異的性能，作為膠水和粘結劑對許多不同的表面。雖然它是高度帶負電荷的離子在中性 pH （支援資訊圖 S5)，仍有一些胺類團體，以保護越來越多的 O 終止表面的雙刷某種程度上。最初，增長因而是仍然在板形式。然而，當 pH 值降在稍後階段 Oterminated表面變得缺乏保護，同時時間在中心原產的偶極子場變得較強的指導生長納米棒形式和折彎沿一個最後的垂直方向的欄位方向 (方案 2)。當添加強簡單電解質，偶極子大大篩選欄位，結構恢復為雙方案 1。雙刷 ZnO mesocrystals 的形成機理的示意圖。化學歐元 J.2012，18，16104 — — 16113 2012年威裡 VCH 出版社 GmbH & 有限公司 KGaA，Weinheim w

結果 (繁體中文) 3:

水解的HMT形成質子化物種（CH2）6n4h +，這是預計將吸附在帶負阿拉伯阿拉伯阿拉伯膠。然而，因為非常低等電點的阿拉伯樹膠，基本上還是負的帶電啟動雙層硝酸鋅氫氧化物水合物的相。那地方是質子化的HMT能够進行進一步水解生成氫氧化物根據所示反應在氧化鋅生長之前。我們建議的物理過程形成機制雙刷的ZnO非晶顯示方案1。在溶液中，鋅離子（方案1）與羥基反應熱分解產生的離子HMT [ 47 ]形成兩種中間顆粒大小不等，從3到5納米。主要的是硝酸鋅水合氫氧化zn5achtungtrenung（NO3）2（OH）8·2H2O）和次要的是氫氧化鈉鋅（OH）2（方案1 B）。然後，由阿拉伯膠介導的納米粒子聚集在一起用表面凹凸不平，形成納米片的厚度約10納米（計畫1 C）。聚合物介導的聚集在水熱條件下觀察到了氧化鋅條件。[ 48 ]在這個過程中，這些納米片自調整形成有序晶體的取向在相變納米片。之後，雙表面層狀納米片直徑約200 nm的表面經歷了表面再結晶（計畫1）。由於長程內在ZnO納米片的偶極場，兩片相反偶極方向連接在一起取消整個雙層納米片利用電場帶負電荷的阿拉伯樹膠作為仲介層。在這一階段，納米片會調整自己的方向的兩個相對的部分之間的小型礦物橋雙層板。此外，zn5achtungtrenung（NO3）2（OH）8·2H2O與偶極特性將疊加在兩個表面上的雙片發生相變之前（計畫1天）。同時，而納米片幾乎全部轉化為氧化鋅，納米棒將形成層狀納米片。囙此，多層的尺寸和厚度納米盤的迅速新增，和表面形貌對非晶雙方也從平到凹（計畫1樓）。多層氧化鋅納米片在整個非晶仍然把他們的擇優取向由於連接他們的小橋。邊緣的凹表面上，雙方都會獲得提供一個吸引非晶中間體的生長場所，其次是兩側形成氧化鋅納米棒（計畫1克）。最後，雙刷ZnO非晶被獲得.最後，我們比較一些現有的作品並總結了反應條件對形態學.首先，在我們的機制雙晶體呈負指控由於氧（0001）平面的表面，這是不受保護的，因為是發現在其他類似的報導納米氧化鋅雙晶體有機陰離子作為添加劑。秋等。最近得到一個氧化鋅的雙晶體形式抗壞血酸作為添加劑[ 49 ]然而，他們的結構往往是多晶無孔不單晶狀和多孔性。顯然，擴散性越小阿拉伯聚合物阿拉伯膠將介導更好的面向連接的在非晶而不是移動了它。一般來說，聚電解質封裝的無機納米晶體能化重視對方更好因為他們有較長的時間來尋找最好的外延配合與融合。在我們以前的工作，準備雙板氧化鋅，明膠的形式使用。明膠既有羧酸酯基團和正電荷胺基。囙此，兩的極性平面（O和Zn終止面）adsorbachtungtrenunged明膠。在C方向的增長，囙此更多抑制和結果在雙板形式。阿拉伯樹膠一個有趣的案例中；它是一種混合糖表現出優异效能的糖蛋白膠水和粘合劑到許多不同的表面。雖然它是高負電荷在中性pH值（支持資訊圖5），還有一些氨基保護雙刷的氧表面生長有些。最初，增長，囙此仍然在板形式。然而，當pH值下降，在後期的oterminated表面變得更少的保護，並在相同的偶極場起源於中心的時間較强的引導生長納米棒形彎曲沿磁場方向（方案2）到最終垂直方向。當加入簡單的强電解質時，偶極場大大篩選和結構恢復到雙—方案1。雙刷的ZnO非晶形成機理示意圖。化學。歐元。J. 2012，1816104161132012威利–VCH出版社有限股份兩合公司，Weinheim