1.0 INTRODUCTION

1.1 Nano-composites

Nano-composites are multiphase materials with one of their element

existing in the dimension less than 100 nanometer because of their low

toxicity, good biocompatibility and excellent biodegradability natural

polymers have important in pharmaceutical applications (Pathania, Kumari

& Kumar, 2015). In the past, studies have been focused more widely of

polymer/layered silicate nano-composites due to their good and often

unique combination of remarkable improved properties, e.g. thermal

stability, protective properties against corrosion, mechanical, flame

retardancy (Hajibeygi, Shabanian, & Ali, 2015) wound dressing,

biosensors, food packaging and air refining (Yadollahi, Farhoudia &

Namazi, 2015).

Hybrid materials with dissimilar phase have at least one dimension at the

nano-scale size regime which is called as nano-composites. The meaning

of “intercalation” is layered nano-composites formed by addition of a

guest anion into the interlayer region of the inorganic interlayers without

changes in the layered structure. Organic-inorganic nano-composites are

strongly inventive structures that provide an indefinite set of new nano-

composites due to the combinations of the organic and inorganic

components (Barahuie, Hussein, Fakurazi, & Zainal, 2014). The nano-

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composites have been applied in many applications such as drug delivery,

photo-catalysis, antibacterial, and tissue engineering. The novel design of

oral controlled drug delivery system has been increased the bioavailability

of drugs (Pathania et al., 2015).

Materials that can be applied as hosts to construct organic-inorganic nano-

composites are layered hydroxides (LHs) which are inorganic and are

composed of nano-layers with two-dimensional infinite layers with nano-

scale thickness besides that offer extensive applications in various areas.

Classified of host-guest layered solids divide by two as layered double

hydroxides (LDH) and layered hydroxide salts (LHS) (Barahuie et al.,

2014). Anionic clay stand for layered double hydroxides (LDHs) was

considered as a class of clays which have a hopeful future in the nano-

composites field because of their various useful properties (Hajibeygi et

al., 2015).

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1.2 Layered Double Hydroxides

Layered double hydroxides (LDHs) also known as anionic clays, is

categories of group of non-silicate compounds. Besides that, one of the most

representative minerals among the group is hydrotalcite, therefore LDHs are

named as hydrotalcite-like compounds (Halajnia, Oustan, Najafi, Khataee, &

Lakzian, 2012). The chemical formula of LDHs is M2+ 1−xM3+ x(OH)2An−

x/n·mH2O and are composed of octahedral M2+(OH)6 brucite-like layers,

which are positively charged by the partial substitution of M3+ for M2+, and

anions are intercalated into the interlayers to attain charge neutrality. A large

number of LDHs have been integrated due to the wide diversity of

combinations of cations and anions possible, e.g. M2+ = Ni, Mg, Co, Cu, Fe,

Cr, Mn, Zn, Cd and Ca, M3+ = Cr, Mn, Al, Co, Fe, Ni,Sc and In, and An− =

F, Cl, Br, I, NO3, SO4 and CO3 (Kameshima, Sasaki, Isobe, Nakajima, &

Okada, 2009). LDHs strictly prefer multivalent anions inside their interlayer

space due to strong electrostatic interaction and hence LDHs bearing

monovalent anions such as nitrate or chloride ions are compatible precursors

for exchange reactions (Choy, Choi, Oh, & Park, 2007).

LDHs is a anionic exchange properties and their stable structure, so have

been widely studied ,for example as anion exchangers, catalyst support ,

drug carriers , electrode materials, absorbents, photo catalysis, optical

materials (Gao, Lei, Hare, Xie, Gao, & Chang, 2013). Otherwise, the

applicability of LDHs in this field is based mainly on three properties are

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increased solubility of the drug, basicity of the LDH matrix, and the ability

for drug controlled release (Rives, del Arco, Martín, Arco, & Martín, 2014).

The properties of these LDHs are high specific surface area (100 ± 300

m2/g), after calcination until temperature reach 500oC under mild condition it

will allows reconstruction of the original structure by induce with solution

containing various anions, it’s called ”Memory effect”, and excellent anion

exchange capacities (Delhoyo, 2007).

The main benefit of these LDHs is that they can boost up the solubility of

the drug and control its release, while supporting them on a polymeric

excipient by decreasing the mobility of ionic drugs and lessens their

aggregation, increasing the influence of the drug on a long time term (San

Román, Holgado, Salinas, & Rives, 2013). Several methods that are

commonly used are the in-situ co-precipitation method in which the

synthesis of LDH happens in the existence of the necessary anionic species

and anionic exchange in which is LDH precursor with NO3− or Cl− as the

anionic species by exchanged counter-anion to form the LDH organic

hybrids (Baikousi, Stamatis, Louloudi, & Karakassides, 2013).

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1.3 Intercalation Process

Intercalation in layered solids is not new due to it’s long established

phenomenon. It has been recommended that the first example, found from

over 2000 years ago, included intercalation in kaolinitesuch as an

aluminosilicate clay and clarifies the secret behind the fine Chinese

porcelain production. Nowadays, a lot of paper shave been dedicated to

intercalation chemistry field in graphite, clay and other materials (Duan et

al., 2006). The word of intercalation show a process in which a molecule or

an ion (guest) is located inside a host lattice. The host structure remains

unchanged or is only slightly give the effect in the guest-host complex that is

in the intercalation compound or intercalate (structure is shown in Figure

1.1). Usually the intercalation reaction is chemically or thermally reversible

such as topotactic, inclusion, insertion reaction are mostly used for the

intercalation reactions (Navrátil, 2015).

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Figure 1.1 Intercalation process occur (Navrátil, 2015).

1.4 Ascorbic Acid

Vitamin C also known as ascorbic acid (structure is shown in Figure 1.2

and Figure 1.3) is existing in many concentrations in all fresh vegetables

and fruits. Ascorbic acid is a water soluble vitamin that have contains a

variety of biological, dermatological and pharmaceutical functions such as,

it scavenge free radical, source of melanin reduction, provide photo-

protection, can promote collagen biosynthesis, improves the immunity

(Liu et al., 2015) and anti-oxidant properties. Human and other mammals

need the ascorbic acid because of It is an essential component in the diet of

them (Singh, Mohanty, & Saini, 2015). Humans and other mammals

cannot produce their own ascorbic acid because of a lack of L-

gulonolactone oxidase. Hence, humans and mammals have to need these

essential vitamins frequently in their diet (Liu et al., 2015).

However, ascorbic acid is very sensitive with presence of air, moisture,

heat, light, oxygen, metal ions, and base. Furthermore, it is easily

decomposed with acidic condition around pH 4.5. Hence, to increase

chemical stability of vitamin C (Chen, Lee, Lin, Lin, & Lin, 2006)

intercalation of vitamin C in the LDHs was investigated by reconstruction,

co-precipitation and ion-exchange need done (Kameshima et al., 2009).

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Figure 1.2 Ascorbic acid molecular structure.

1.5 Problem statement

Ascorbic acid or so called vitamin C is a water soluble vitamin and can give

advantages of our most important body systems. For example, it can

provide photo-protection, promote collagen biosynthesis, enhance the

immunity, cause melanin reduction, and free radical of scavenge (Chen et

al., 2006). Besides that, human body requires only a little amount of

ascorbic acid for physiological functions. Lack and excessive supplies of

ascorbic acid lead to harmful effects on human body such as ascorbic acid

might sickle of cell disease, kidney stones and blood sugar become raise.

Ascorbic acid, however, is very unstable to air, base, heat, light, moisture,

metal ions, and effecting in decomposition to biologically in active

compounds (Gao, Lei, Hare, Xie, Gao, & Chang, 2013). To overcome the

decomposition of ascorbic acid, the ascorbic should be stored in storage.

Therefore, intercalating the ascorbic acid into the interlayer of LDH can be

applied to solve this problem.

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1.6 Significant of Study

This study aimed to develop a new system for drug controlled release

formulation by using layered double hydroxide as the drug carrier because

of the positively layered of the LDHs, it has potential to be used as the host

for the negatively charged of ascorbic acid anion for the controlled release

formulation. The encapsulation system is able to ascorbic acid stable to air,

moisture, light, heat, metal ions, and base. The drugs are expected to be

thermally more stable due to the electrostatic attraction between the

positive metal hydroxide layer and the intercalated anion and the hydrogen

bond formed between water and the ascorbic acid anion.

1.7 Objectives of Study

The objectives of project are:

a) To study the intercalation of LDH-ascorbic acid through co-

precipitation method.

b) To characterize the ascorbic acid by using Powder X-Ray Diffraction

(PXRD), Fourier Transform Infrared Spectroscopy (FTIR) and

Carbon, Hydrogen, Nitrogen, Sulphur (CHNS).

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2.0 LITERATURE REVIEW

2.1 Historical Background

Layered hydroxides consist of two types which are layered hydroxide salts

and layered double hydroxides are synthesis from a brucite layered

structure, which is a natural from magnesium hydroxide and was first

discovered in 1824 (Barahuie et al., 2014) was reported by Hochstetter

synthesized 100 years later by Feitknecht (July, 2015). Feithnecht is

derived the name of LDH from the early works of and his called these

compounds by “Doppelschichtstrukturen” meaning of this word is double

sheet structures, hypothesizing a structure through intercalated hydroxide

layers (Delhoyo, 2007).

In nature, from the weathering of basalts (a types of dark rock that comes

from volcano) produces LDHs in saline water sources by precipitation..

LDHs can be also readily synthesized in the laboratory using co-

precipitation methods (Baikousi et al., 2013), anionic exchange method

(Rives et al., 2014), reconstruction method (Kameshima et al., 2009).

Broad class of inorganic lamellar compounds also has known LDHs with

basic properties with high capacity for intercalation of anion. The structure

of LDHs known as hydrotalcitelike compounds because of their structural

same to hydrotalcite, a mineral with the formula Mg6Al2(OH)16CO3·4H2O.

from the result hydrotalcite structure the stacking of brucite like layers

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[Mg(OH)2] having a positive residual charge arising from the partial

isomorphous substitution of Mg2+ cations by Al3+ cations. Carbonate anions

from positive excess charge is balanced by the, which be located in the

interlamellar spaces (July, 2015).

LDHs have deserved in the last decades an increasing interest due to of

their applications in many fields (Rives, Del Arco, & Martín, 2013) based

mainly on three properties: improved the solubility of drug, basicity of the

LDH matrix, and capacity for drug controlled release. the addition usually

the solubility of the drugs can increases by LDHs (Rives et al., 2014).

LDHs is biocompatible inorganic materials and mostly used in drug

delivery and controlled release systems because of these materials are more

stable and less toxic than conventional drug carriers (Gao, Lei, Hare, Xie,

Gao, Chang, et al., 2013). The main benefit of these LDHs is that they

increase the solubility of the drug and control its release, the mobility of

ionic drugs is reduces and their aggregation is reduces while supporting

them on a polymeric excipient, besides that, the effect of the drug on a long

time term is increasing (San Román et al., 2013).

LDHs commonly used as host materials to produced biomolecule/

inorganic hybrids has enticed considerable interest because of their

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properties which are excellent biocompatibility, less cytotoxicity and their

has good framework structure which gives strong protection for the loaded

biomolecules inside the layer (Baikousi et al., 2013).

2.2 Structure of Layered Double Hydroxide

The general structural formula for LDHs compounds is [M2+ 1−xM3+

x(OH)2]x+ [Am− x/m·nH2O]x−, where M2+ and M3+ are divalent and trivalent

cations. The value of x is equal to M3+/(M2++M3+) and Am− is a charge

balancing interlayer anion. In the majority of cases the x values change

between 0.10 and 0.33. These compounds exhibit an excellent ability to

trap organic and inorganic anions due to the presence of positively charged

brucite-like sheets, relatively weak interlayer bonding and ion-exchange

properties (Halajnia et al., 2012).

Regarding the anions, their diameter size/charge ratio is very significant, as

large anions with low charge are unable to balance homogeneously the

positive charge of the layers. A compromise should be reached between the

layer charge density (cations) and the dimensions of guests’ species

(anions) in the interlayer. For non-spherical anions, and especially when the

long chains of anions such as carboxylates or sulfonates with long alkyl

chains, several arrangements in the interlayer are probable, namely, a

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monolayer parallel to the layers, a parallel bilayer or tilted monolayers or

bilayers (Rives et al., 2014).

The structure of LDHs described by drawing analogy with the structural

features of the metal hydroxide layers in mineral brucite or simply the

Mg(OH)2 crystal structure. Brucite contains of a hexagonal close packing of

hydroxyl ions with Mg2+ ions occupied in alternate octahedral sites. The

metal hydroxide sheets in brucite crystal are without charge and Van der

Waals interaction is hold one upon another. The value of interlayer distance

or the basal spacing in brucite has a about 0.48 nm. Besides that’s, in LDH,

several of the divalent cations of these brucite-like sheets are

isomorphously replaced by a trivalent cations and the combined metal

hydroxide layers, [MII 1−xMIII x(OH)2]x+, thus formed gain a net positive

charge. This extra charge on the metal hydroxide layers is neutralized by

the anions stored in the interlayer region. Some water molecule can also be

found in the interlayer region in LDHs for the crystal structure stabilization.

The existence of anions and water molecules effect the enlargement of the

basal spacing from 0.48 nanometer in brucite to around 0.77 nanometer in

Mg-Al-LDH acid as shown in Figure 2.1 (Costa et al., 2005).

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The basal spacing of LDHs can define as;

dspacing = dlayer + dinter

Where dlayer shows the thickness of the hydrotalcite brucite-like LDH sheet,

and the dinter includes the length of intercalated species and absorptive water

between the layer (Xiong et al., 2015).

It is limitless in term of the nature of the interlayer anions also the system

with variety species of anionic are known inorganic anion (lactate,

terephthalate, acrylate and etc.), simple inorganic anions (halide,

carbonate, nitrate and etc.) coordination compound, biomolecule,

polyoxometaletes as example nucleoside monophosphates (adenosine

triphosphate, guanosine monophosphate, cytosine monophosphate, and

adenosine monophosphate) thus deoxyribonucleic acid fragment itself have

been intercalated with success (Rives et al., 2013).

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Figure 2.1: Schematic illustration comparing the crystal structure of brucite(A) and LDH (B) (Costa et al., 2005).

2.3 Synthesis of Layered Double Hydroxide

2.3.1 Co-precipitation method

Consisting of the slow addition of solution containing salts the

metal cations solution (Rives et al., 2013) into a container

containing the anion to be intercalated and addition of a base or

urea hydrolysis that leads to precipitation of the LDH make the

increasing of the pH values (Rives et al., 2014). The most common

method use by synthesis of LDH preparation by co-precipitation at

constant pH is to obtain various types of synthetic LDH because of

this method usually has greatly reasonable results, good structural

organization and phase purity of structure LDHs can be obtained

(Morais & Aquino, 2015). The organic ions and molecules is to big

than inorganic ions, such an intercalation is preferably most

suitable by reconstruction than ion-exchange method (Kameshima

et al., 2009). By method co-precipitation can achieve three times

(most useful) yield compare to method reconstruction method

(Nalawade, Aware, Kadam, & Hirlekar, 2009).

2.3.2 Ion exchange in solution method

From co-precipitation method, an anionic exchange of anions

originally existing in the interlayer of a LDH. the original anions

such as chloride or nitrate, as the exchange is much easier than

compare to multi-charged anions (Rives et al., 2014). The influent

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of electrostatic interactions between the layers and the interlayer

anions can effect of exchanging the anions in LDHs. Increase the

equilibrium constants as the ionic radius of the anion become

decreases. The diffusion of the in-going anions inside the interlayer

is the rate-determining step (Rives et al., 2013). The exchanged

anion will have the maximum ability to stabilize the lamella (more

probable to be intercalated) and/or be in a higher proportion than

the LDH precursor anion, such as Cl− or NO−3 (Morais & Aquino,

2015). Several factor can affect the ion-exchange process such as

incoming anion affinity, exchange media, pH value, chemical

composition (Barahuie et al., 2014).

2.3.3 Hydrothermal method

The method of hydrothermal is commonly used during the

preparation or intercalation process to control particle size and size

distribution because to produce LDHs with standardise of size and

high crystallinity (Barahuie et al., 2014). The main advantage of

this method, when compared with other coprecipitation method, is

to avoid unwanted waste discard, which may be unsafe to the

environment, such as the anion NO−3, Cl−, OH− , etc (Morais &

Aquino, 2015).

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2.4 Applications of Layered Double Hydroxide

Nowadays, the technology of nanostructures involved often combine

captivating shapes with remarkable properties. With the combination of new

techniques and novel concepts for preparation of LDH structures, together

with the requirements of practical applications, various studies focus on the

properties and applications of nanostructured LDHs (Kuang et al., 2010).

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LDHs

Medicine

Catalyst

Catalyst

supportIndustry

Absorbent

Figure 2.1 Main industrial applications of LDHs (Delhoyo, 2007).

2.4.1 Catalyst

LDHs can include a wide number of elements homogeneously

dispersed with controlled proportions so they are very widely used

in catalysis, as they allow the synthesis of tailored catalysts.

Hydrotalcites are commonly used in heterogeneous catalysis as

synthesised, as catalyst supports and as catalyst precursors. Oxides

that synthesised by process of calcination of hydrotalcites indicate

wide compositional ranges, the elements is homogeneous

dispersion, preserved even after moderate thermal treatments or

reduction, high specific surface areas (100–130 m2/g) or memory

effect, causing them to become more attractive than other oxides

gained through conventional methods. They have been used in

basic catalysed reactions and to make fine chemicals and

intermediates (Rives et al., 2013). Strong basic properties is

displayed by original LDHs and can be applied as heterogeneous

catalysts, to avoid environmental harm when using soluble basic

catalysts (Rives et al., 2014).

The structured of LDH powder, LDH film, and activated

rehydrated LDH (RLDH) which is well-known as effective solid

catalysts, used the Cu2+ based LDH powder as a catalyst for wet

oxidation , and stated that the array of active Cu2+ centers on the

surface of CuZnAl-CLDH that is ordered net-shaped, which is

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influenced by the effect of ordered cross-trap. The benefits of novel

LDH films are able to overcome the problems of powdery use

catalysts on an industrial scale, which are high pressure drop and

catalyst separation is difficult (Kuang et al., 2010).

2.4.3 Medicine

Biologically-active molecules show a property that has opened

their applications in medicine and pharmacy, are also among the

different sorts of molecules which can be intercalated between the

brucite like layers of LDHs (Rives et al., 2014). For example, p-

amino benzoic acid intercalated in Mg, Al or Zn, Al hydrotalcites

evades skin reactions such as irritation, urticaria, contact

dermatitis, etc., avoiding degradation to carcinogenic nitrosamines

and extending its photo-stability, and maximise the protection in

the ultra-violet A range (Rives et al., 2013).

These LDHs are synthesized from biocompatible metal elements

and have pH-dependent solubility, thus they can easily be

decomposed in the acidic biological environment. As their anion

exchange property allows loading of various drugs into the

interlayer lamellae of LHs, it can lead to modification of the charge

density of the internal and external surfaces, thus effecting in

greater chemical stability, cell targeting function, and high surface

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area (Barahuie et al., 2014). However, numerous of the divalent

and trivalent metal cations that can form LDHs, have low toxicity.

The most commonly used as a LDH-based drug carrier are MgAl–

LDHs (Bi, Zhang, & Dou, 2014).

2.4.4 Water treatment

Waste water is harmful to both humans and wildlife because they

often contain oxyanions such as F–, Cl–, Br–, PO4-3. Therefore,

hydrotalcites is used to adsorb polluting anions from aqueous

solutions, while the mixed oxides formed upon calcination is used

to scavenge anions from solutions on recovering the layered

structure (Rives et al., 2014). Enhanced ability to remove

oxyanions is important in environmental protection. Structured

LDHs can be a new type of promising material due to their ability

to capture organic and inorganic anions that can be used in water

treatment. The main benefits of LDHs over the conventional

anionic exchange resins are their higher anion exchange capacity

for certain oxyanions and their good thermal stability (Bi et al.,

2014).

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2.4.5 Flame retardant

Powdery LDH is also profitably promising as an additive in flame

retardants. Many flame retardants are considered harmful, having

been related to liver, thyroid, reproductive/developmental, and

neurological effects. Presently, halogen-free alternatives are one

active research area. LDHs and cationic clays for example

montmorillonite have been commonly investigated as additives in

this context. Compared to other flame retardants, LDH can be a

new type of material because of properties such as high smoke

suppression, nontoxicity or low toxicity. LDH is now discovered as

a second generation flame retardant with enhanced properties by

either modification of the layers or intercalation of diverse anions

(Kuang et al., 2010).

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3.0 METHODOLOGY

3.1 Materials

Chemical use in this experiment is ascorbic acid, aluminium nitrate,

alcohol, zinc nitrate, hydrochloric acid, zinc oxide. Nitrogen gas use to

avoid the carbonate contamination.

Chemical Brand

Ascorbic acid Sigma Aldrich

Aluminium Nitrate R & M

Alcohol R & M

Zinc nitrate R & M

Hydrochloric acid R & M

Zinc oxide R & M

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Table 3.1 List of the chemical use

3.2 Synthesis of Zn-Al-LDH

Zn(NO3)2 will mix with Al(NO3)2 in the conical flask and the titrate with

NaOH until reach at pH 7.5 ± 0.2. The nitrogen gas is purge into the

mixture to prevent co-intercalation of CO2 from the atmosphere. Add the

ascorbic acid is gradually by using a dropper. At pH 7.5 the titration

process will be stop (Aisawa et al., 2007).

The slurry obtain is aged for 18 hours in an oil bath shaker then it is cooled,

centrifuged and wash with deionises water. Next, it is calcine at various

temperatures. After that, the precipitation is collect and dry in an oven at

70oC and the sample will be keep for further characterization by using the

instrumentation such as PXRD, FTIR and CHNS.

23

24

Zn(NO3)2 will mix with Al(NO3)2 in conical flask. Titrate with NaOH until reached at 7.2

The nitrogen gas is purge into the mixture to prevent co-intercalation of CO2 from the atmosphere. Add the ascorbic acid gradually using a dropper

When the ph reached value stop the titration. The slurry obtaine is aged 18 hours in an oil bath shaker

Then it is cool, centrifugedand wash by deionised water. Then its calcined at various temperature

Collect the precipitation and dried at temp 70o C. The sample will be keep for further characterization by using PXRD,FTIR,CHNS

Figure 3.1 Flowchart of Synthesis of Zn-Al-LDH.

3.3 Synthesis of Nano-Composite by Self-Assembly Method

The previous pre-prepared LDH and ascorbic acid solution will mix

together in a conical flask at various concentrations. Stir the mixture

vigorously for 2 hours in an oil bath shaker under nitrogen gas atmosphere.

Next, the mixture is cool and centrifuge and dry in an oven. After the

mixture dry, it is keep for further characterization by using the powder X-

Ray diffraction (PXRD), Fourier transform-infrared (FTIR), Carbon,

Hydrogen, Nitrogen, Sulphur (CHNS).

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The previous pre-prepared LDH and ascorbic acid solution willmix together in a conical flask at various concentrations.

Stir the mixture vigorously for 2 hours in an oil bath shaker under N2 atmosphere. Next, the mixture is cool and centrifuge and dry in an oven.

After the mixture dry, it is keep for further characterization by using the powder X-Ray diffraction (PXRD), Fourier transform-infrared (FTIR), carbon

hydrogen nitrogen sulphur (CHNS).

Figure 3.2 Flowchart to synthesis of nano-composite by self-assembly method.

3.4 Physico-Chemical Analysis and Characterizations

3.4.1 Powder X-Ray Diffraction (PXRD)

X-Ray diffraction refers to the units of crystalline solid scattering

by X-Ray. The scattering of diffraction created is used to deduce

the particles arrangement. The upper wave is scattered, or

reflected, by an atom in the first layer while the lower is scattered

by an atom in the second layer. In order for these two waves to be

in phase again, the extra distance travelled by the lower must be

integral multiple of the wavelength (λ) of the X-Ray, that is,

BC+CD = 2d sin θ = nλ where n = 1,2,3,… its nano-composite

(structure is shown in Figure 3.3).

Figure 3.3 Reflection of X-Ray from two layers of atoms.

The basal spacing, crystallinity and purity of the compounds can be

obtaine by this tecnique. PXRD spectra will be recorded on a

Rigaku XRD-6000 powder diffraction unit using filtere Cu-Kα

radiation (λ = 1.54 Å), at 40 kV and 30 mA. A continuos scanning

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rate is set at 2 degrees per second within a range of 2 to 60

degrees. The PXRD technique is used to determine the increase in

the basal spacing at 2θ =5o due to the intercalation of ascorbic

anion into the interlamellae of Zn-Al-layered double hydroxide.

The basal spacing expended from 8.9 Å to a bigger basal spacing

value when nitrate ion is replaced by ascorbic acid ion during the

intercalation process in the formation of the nanocomposite.

3.4.2 Fourier Transform-Infrared (FTIR)

Atom or atomic groups in molecules are in continuos motion with

respect to each other. These motions are twisting, bending and

vibrational of atoms in a molecule. Upon interaction with infrared

radiation, portions of the incident radiation are absorbed and a

signal is abserved in the infrared spectrum if the dipole momentum

of the molecule changes during interaction with the

electromagnetic radiation. The absorbed wavelength are specific

for a particular atom present in a molecule. The multiplicity of

vibrations spectrum which is uniquely characteristic of the

functional group of the molecule.

The resulting pellet was inserted into a sample compartment before

analysis is begin. FTIR analysis id used determined the presence of

functional group of any intercalated organic compound in the

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interlamellae of the nano-composite. The instrument empoyed for

this analysis wll be Perkin-Elmer models 1725X spectrophotometer

in the range of 4000-400 cm-1.

3.4.3 Carbon, Hydrogen, Nitrogen, Sulphur (CHNS) Analysis

CHNS analysis is carry out by using CHNS-932 LECO to

determine the content of carbon, hydrogen, nitrogen and sulfur in

the sample. In CHNS analysis, the tecniques use is Dynamic Flash

Combustion. The sample is weight in the range of 1.200 to 2.000

mg and place in a tin capsule which is drop into quartz tube at

1020oC with constant helium flow as the carrier gas. The CHNS

analysis technique is used to determine the percentage weight of

carbon and nitrogen in the nano-composite. The intercalation of

ascorbic acid ion could be comfirm by the increase of carbon

content in the Zn-Al-ascorbic acid nano-composite.

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Cited References

Aisawa, S., Higashiyama, N., Takahashi, S., Hirahara, H., Ikematsu, D., Kondo, H., … Narita, E. (2007). Intercalation behavior of l-ascorbic acid into layered double hydroxides. Applied Clay Science, 35(3-4), 146–154. http://doi.org/10.1016/j.clay.2006.09.003

Baikousi, M., Stamatis, A., Louloudi, M., & Karakassides, M. a. (2013). Thiamine pyrophosphate intercalation in layered double hydroxides (LDHs): An active bio-hybrid catalyst for pyruvate decarboxylation. Applied Clay Science, 75-76, 126–133. http://doi.org/10.1016/j.clay.2013.02.006

Barahuie, F., Hussein, M. Z., Fakurazi, S., & Zainal, Z. (2014). Development of Drug Delivery Systems Based on Layered Hydroxides for Nanomedicine, 7750–7786. http://doi.org/10.3390/ijms15057750

Bi, X., Zhang, H., & Dou, L. (2014). Layered Double Hydroxide-Based Nanocarriers for Drug Delivery, 298–332. http://doi.org/10.3390/pharmaceutics6020298

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