Silica Polymer Research Articles

Effects of Hairy Nanoparticles on Polymer Crystallization Kinetics

We previously showed that nanoparticles (NPs) could be ordered into structures by using the growth rate of polymer crystals as the control variable. In particular, for slow enough spherulitic growth fronts, the NPs grafted with amorphous polymer chains are selectively moved into the interlamellar, interfibrillar, and interspherulitic zones of a lamellar morphology, specifically going from interlamellar to interspherulitic with progressively decreasing crystal growth rates. Here, we examine the effect of NP polymer grafting density on crystallization kinetics. We find that while crystal nucleation is practically unaffected by the presence of the NPs, spherulitic growth, final crystallinity, and melting point values decrease uniformly as the volume fraction of the crystallizable polymer, poly(ethylene oxide) or PEO, ϕPEO, decreases. A surprising aspect here is that these results are apparently unaffected by variations in the relative amounts of the amorphous polymer graft and silica NPs at constant ϕ, implying that chemical details of the amorphous defect apparently only play a secondary role. We therefore propose that the grafted NPs in this size range only provide geometrical confinement effects which serve to set the crystal growth rates and melting point depressions without causing any changes to crystallization mechanisms.

Structure of Silica Polymers and Reaction Mechanism for Formation of Silica-Rich Precipitated Phases in Direct Aqueous Carbon Mineralization

This research aims to provide insight into the structure and reaction mechanism of silica-rich phases formed as byproducts in direct aqueous carbonation of heat-activated lizardite. In undertaking this work, we employed analytical techniques such as thermogravimetric analysis (TGA), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), 29Si solid-state nuclear magnetic resonance (29Si SS NMR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to characterize carbonation products and to understand the mechanism of formation and the structure of silica-rich byproducts. Thermodynamic analysis predicts the formation of magnesite and amorphous silica in the process of direct aqueous carbonation of heat-activated lizardite under the experimental conditions studied. Characterization of carbonat...

Glass Transition and Molecular Dynamics in Core–Shell-Type Nanocomposites Based on Fumed Silica and Polysiloxanes: Comparison between Poly(dimethylsiloxane) and Poly(ethylhydrosiloxane)

The interfacial polymer in nanocomposites (PNCs) is widely believed to exhibit modified dynamics and structure, which are considered responsible for the improved PNC properties. Owing to its high resolving power, broadband dielectric spectroscopy (BDS) is one among the most suitable tools for studying polymer dynamics. Here, BDS combined with differential scanning calorimetry (DSC), microscopy, infrared spectroscopy, and thermally stimulated depolarization currents (TSDC) are employed to study low-molecular weight polydimethylsiloxane (PDMS) and a slightly modified siloxane, polyethylhydrosiloxane (PEHS), in bulk and in the form of silica–polymer “core–shell”-type PNCs. The dielectric/calorimetric mapping for the systems based on PEHS is demonstrated for the first time. Bulk-like dynamics (α relaxation, glass transition) is recorded faster and less cooperative in the PNCs, in agreement between the techniques, most probably due to spatial confinement between the neighboring nanoparticles. The constraints a...

Selective extraction and detection of norfloxacin from marine sediment and seawater samples using molecularly imprinted silica sorbents coupled with HPLC.

A simple, sensitive and effective method was developed and validated for selective adsorption and quantitation of norfloxacin (NFX) from marine sediments and seawater samples using the novel molecularly imprinted silica polymers as sorbents followed by high-performance liquid chromatographic analysis with diode array detection (HPLC-DAD). The imprinted particles were characterized by different techniques and the molecular recognition for NFX was also investigated. Several parameters affecting the extraction efficiency of molecularly imprinted solid-phase extraction (MISPE) process were optimized. Three sediment and seawater samples from Weihai bay in China were analyzed and the results show that satisfactory recoveries (77.2-98.7%) were achieved in seawater samples with low relative standard deviation (RSD) values less than 6.89% (n = 3), and the recoveries in sediments were in the range of 75.5-91.7%. The limits of detection are respectivley 2 μg L-1 in seawater samples and 5 μg kg-1 in sediments.

Multifunctional Silica-Silicone Nanocomposite with Regenerative Superhydrophobic Capabilities.

Superhydrophobic surfaces have been garnering increased interest because of their adaptive characteristics. However, concerns regarding their durability and complex fabrication techniques have limited their widespread adoption. In our study, we have developed an effective, durable, and versatile silica-silicone nanocomposite that can be applied through spray coating or bulk synthesized as superhydrophobic monoliths through a facile, economic, and scalable fabrication technique. For spray-coated samples, superhydrophobicity was achieved for concentrations above 9%. However, poor adhesion was observed for concentrations above 20%. Through extensive surface morphology studies, it was determined that a delicate balance between the polymer and dispersed superhydrophobic silica nanoparticles exists at a concentration of 14%. This concentration is necessary for developing the desired hierarchical structure and providing sufficient adhesion with the substrate. The monoliths were fabricated into complex geometries, with superhydrophobicity being observed in the 5 and 9% specimens. The hierarchical structure was formed through controlled surface abrasion, which created the microscale roughness and concurrently exposed the embedded silica nanoparticles. It was found that a monolith with a concentration of 9% provides excellent water repellency as well as a suitable emulsion viscosity to facilitate the molding process. Though compressive loading (up to 10 MPa) damages the monolith, the superhydrophobic performance can be quickly restored through abrasive layer removal. Both spray-coated and monolith specimens retained their superhydrophobicity after being subjected to high temperatures (up to 350 °C) and corrosive environments (pH 1-13) for 2 h.

Silica Removal Using Magnetic Iron-Aluminum Hybrid Nanomaterials: Measurements, Adsorption Mechanisms, and Implications for Silica Scaling in Reverse Osmosis.

Composite magnetic aluminum hydroxide at iron oxide nanomaterials, Al(OH)3@Fe3O4, with a well-defined core-shell structure, were used as pretreatment adsorbents for the removal of silica in brackish water. The Al(OH)3 outer shell confers silica adsorption capacity, and the superparamagnetic Fe3O4 core allows material separation and magnetic recovery. The as-prepared nanomaterials (2 g L-1) remove ∼95 and ∼80% silica from Si-rich solutions with 0.5 and 2 mM initial silica concentrations, respectively. Regeneration under basic conditions was evaluated, and post-adsorption treatment with 0.05 M NaOH yielded optimal material reusability. After four regeneration cycles, the Al(OH)3@Fe3O4 nanomaterials retain their magnetic property while still being able to remove ∼40% silica from solutions at an adsorbent concentration of 2 g L-1. The mechanism of silica adsorption onto the surface of the nanomaterials was probed using several spectroscopic techniques. ATR-FTIR (attenuated total reflection-Fourier transform infrared) integrated with two-dimensional correlation analysis shows that silica species vary from Q2 to Q4 with adsorption time corresponding to silica polymerization. 29Si solid-state NMR spectra show an upfield chemical shift displacement of the Q2 signal, which indicates the formation of Q4 units, suggesting silica polymerization onto the Al(OH)3 shell. In addition, a laboratory-scale reverse osmosis setup was used to evaluate Al(OH)3@Fe3O4 as pretreatment materials for silica removal. Results show that silica scaling was significantly alleviated, and water recovery was enhanced when feed waters were pretreated with the magnetic nanomaterials. Taken together, our study highlights the promise of magnetic Al(OH)3@Fe3O4 nanomaterials in treating brackish water and achieving higher water recovery for inland desalination.

Molecular Dynamics Simulation Study of Solid Vibration Permeation in Microporous Amorphous Silica Network Voids.

Microporous silica membranes have silica polymer network voids smaller than 3 Å where only small gas molecules such as helium (2.6 Å) and hydrogen (2.89 Å) can be transported. These silica membranes are highly expected to be available for H2 separation. In order to examine gas permeation mechanisms in the silica polymer network voids, factors such as membrane porous structures, gas diffusivity, and gas permeability were studied via membrane permeation molecular dynamics simulation. The thermal motions of silica membrane constituent atoms were examined according to classic harmonic oscillation potential using a suitable amorphous silica structure and non-equilibrium molecular dynamics (NEMD) simulations of gas permeation. The dynamic model successfully simulated the gas permeation characteristics in an amorphous silica membrane with a suitable Hooke’s potential parameter. The introduction of the oscillative thermal motion of the membrane atoms enhanced gas diffusivity. Helium and hydrogen diffusivity and permeability were analyzed using gas translation (GT) and solid vibration (SV) models. The diffusion distance of gas molecules between adsorption sites was around 5.5–7 Å. The solid-type vibration frequencies of gas molecules in the site were on the order of 1013 and were reasonably smaller for heavier helium than for hydrogen. Both the GT and SV models could explain the temperature dependency of helium and hydrogen gas diffusivities, but the SV model provided a more realistic geometrical representation of the silica membrane. The SV model also successfully explained gas permeability in an actual silica membrane as well as the virtual amorphous silica membrane.

Water repellent finishing on eri silk fabric using nano silica

Nano silica was extracted from rice husk and applied on eri silk fabric to impart water repellency. The efficiency of the water repellency was evaluated with water contact angle, water absorbency and spray test methods. In order to enhance the water repellent properties, a silicone-based polymer was also applied. The effect of nano silica coating on the physico-mechanical properties of the eri silk fabric was studied using standard methods. SEM, FTIR and EDX techniques were used for the confirmation of presence of nano silica on silk fabric. The results inferred the nano silica imparted hydropholic property to eri silk fabric, which was further enhanced to superhydrophobic by the incorporation of silica polymer. The nano silica coating slightly enhanced the whiteness and brightness of eri silk fabric. Other mechanical parameters like bending rigidity and crease recovery angle were found to be intact. The higher concentration of nano silica caused a slight reduction in fabric tensile strength.

The Effect of Polydimethylsiloxane-Ethylcellulose Coating Blends on the Surface Characterization and Drug Release of Ciprofloxacin-Loaded Mesoporous Silica.

In this study, we obtained novel solid films composed of ciprofloxacin-loaded mesoporous silica materials (CIP-loaded MCM-41) and polymer coating blends. Polymer coating blends were composed of ethylcellulose (EC) with various levels of polydimethylsiloxane (PDMS, 0, 1, 2% (v/v)). The solid films were prepared via the solvent-evaporation molding method and characterized by using scanning electron microscopy (SEM), optical profilometry, and wettability analyses. The solid-state of CIP present in the solid films was studied using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The release profiles of CIP were examined as a function of PDMS content in solid films. The surface morphology analysis of solid films indicated the progressive increase in surface heterogeneity and roughness with increasing PDMS content. The contact angle study confirmed the hydrophobicity of all solid films and significant impact of both PDMS and CIP-loaded MCM-41 on surface wettability. DSC and XRD analysis confirmed the presence of amorphous/semi-crystalline CIP in solid films. The Fickian diffusion-controlled drug release was observed for the CIP-loaded MCM-41 coated with PDMS-free polymer blend, whereas zero-order drug release was noticed for the CIP-loaded MCM-41 coated with polymer blends enriched with PDMS. Both the release rate and initial burst of CIP decreased with increasing PDMS content.

A Study of the Optical Properties of a Multimode Silica Optical Fiber with a Reflective Shell from a Fluorinated Thermoplastic Polymer

The optical properties of a silica–polymer optical fiber with a light-guide core with a diameter of 430 μm and a reflecting shell with a thickness of 70 μm from a thermoplastic copolymer of tetrafluoroethylene with ethylene of Tefzel brand have been experimentally studied. The polymer coating is applied to a silica fiber directly in the fiber draw apparatus by the die method from a thermoplastic melt. The optical losses of the drawn fiber and the numerical aperture and its dependence on the fiber length are measured. It is established that a light propagating through the fiber is noticeably scattered by the reflecting shell, which is associated with the crystallinity of the polymer. The distribution of the scattered radiation intensity along the fiber axis and the indicatrix of radiation scattering by the shell are measured. The relative contributions of scattering and absorption of light in the shell to the total optical losses of the fiber are estimated. The possible use of optical fibers of this structure in laser medicine is considered.

Formation of root silica aggregates in sorghum is an active process of the endodermis.

Silica deposition in plants is a common phenomenon that correlates with plant tolerance to various stresses. Deposition occurs mostly in cell walls, but its mechanism is unclear. Here we show that metabolic processes control the formation of silica aggregates in roots of sorghum (Sorghum bicolor L.), a model plant for silicification. Silica formation was followed in intact roots and root segments of seedlings. Root segments were treated to enhance or suppress cell wall biosynthesis. The composition of endodermal cell walls was analysed by Raman microspectroscopy, scanning electron microscopy and energy-dispersive X-ray analysis. Our results were compared with in vitro reactions simulating lignin and silica polymerization. Silica aggregates formed only in live endodermal cells that were metabolically active. Silicic acid was deposited in vitro as silica onto freshly polymerized coniferyl alcohol, simulating G-lignin, but not onto coniferyl alcohol or ferulic acid monomers. Our results show that root silica aggregates form under tight regulation by endodermal cells, independently of the transpiration stream. We raise the hypothesis that the location and extent of silicification are primed by the chemistry and structure of polymerizing lignin as it cross-links to the wall.

Tunable Chemical and Topographic Patterns Based on Binary Colloidal Crystals (BCCs) to Modulate MG63 Cell Growth

AbstractMore effective and diversified surface modification strategies are required for materials used in biomedical engineering. Combining surface modification involving bioactive signals or nonfouling polymers with tunable topography has the potential to meet this need. Here, a method is reported to generate bioactive surfaces having tunable topographies based on self‐assembled binary colloidal crystals (BCCs), where the colloids are premodified with nonfouling molecules or cell adhesive peptides. The BCCs are fabricated from silica (Si) microspheres and polymer nanospheres. The Si microspheres are either modified with poly(ethylene glycol) (PEG) or with the cell adhesive arginine–glycine–aspartic acid (RGD) peptide prior to BCC fabrication. Four types of BCCs are explored in cell studies using MG63 cells. BCC surfaces coupled with PEG or RGD peptides are found to significantly modulate cell adhesion, spreading, and morphology, which is attributed to the combination of BCC topography and the molecules at the particle surface within the BCC. PEG‐modified BCCs are expected to find applications where limited cell adhesion is required, while the RGD‐modified BCCs have the potential for enhancing cell growth on medical devices such as bone implants. More advanced cell biology applications such as controlled stem cell differentiation are also anticipated to find use from BCCs.

Integrated soluble polymer and mesoporous silica as a double–type support to immobilize tertiary amine–Ru/diamine–bifunctionality for aza–addition/reduction cascade reaction

Exploiting advantages of a double–type support to create an active site–isolated heterobifunctional catalyst is beneficial to an efficiently sequential organic transformation. Herein, an integrated soluble polymer and mesoporous silica as a double–type support to immobilize the tertiary amine–Ru/diamine–bifunctionality for the construction of an active site–isolated catalyst is developed, where the tertiary amine–functionality is tethered in the outer soluble polymer and chiral ruthenium/diamine–functionality is anchored within the inner mesoporous silica. Electron microscopy images, together with analyses of solid–state NMR spectra, disclose that catalyst possesses the uniformly distributive morphology with well–defined single–site ruthenium/diamine active centers. As envisaged, the heterobifunctional catalyst performs a highly efficient aza–Michael addition/asymmetric transfer hydrogenation enantioselective cascade reaction, where the outer tertiary amine–functionality enables a high reactivity to afford β–secondary amino ketones via an aza–Michael addition reaction of enones and amines, and the inner chiral ruthenium/diamine–functionality guarantees a high enantioselectivity to chiral γ–secondary amino alcohols via an asymmetric transfer hydrogenation of β–secondary amino ketones. Furthermore, this catalyst can also be recovered easily and recycled for six runs, showing a practical preparation of aryl–substituted γ–secondary amino alcohols.

Synthesis of a polymeric imidazolium-embedded octadecyl ionic liquid-grafted silica sorbent for extraction of flavonoids

In this work, a polymeric imidazolium-embedded octadecyl ionic liquid (poly(1-vinyl-3-octadecylimidazolium naphthalene sulfonate))-grafted silica (poly(C18VIm+NapSO3−)@SiO2) sorbent was prepared and applied as a solid-phase extraction (SPE) sorbent in extraction of flavonoids. The synthesized poly(C18VIm+NapSO3−)@SiO2 sorbent was characterized by X-ray photoelectron spectrogram (XPS) and fourier transform infrared spectroscopy (FT-IR). The thermodynamic and kinetic adsorption models of the prepared poly(C18VIm+NapSO3−)@SiO2 sorbent towards flavonoids were discussed by nonlinear fitting adsorption curve and the results indicated the thermodynamic adsorption model in this work was tended to be Freundlich model rather than Langmuir one and the pseudo-second order model could be used to describe the dynamic adsorption process. In addition, the adsorption amounts indicated the sorbent has satisfactory extraction capabities towards flavonoids. For investigating the influence of independent variables and their interactions on the extraction efficiency, a Box-Behnken design was used for optimizing three greatly influential parameters after performing single-factor experiments. The interaction energies between flavonoids and two ionic liquids were calculated to understand the adsorption mechanism. Under the optimal conditions, a method used for determining flavonoids was developed by combining SPE technique with high performance liquid chromatography (HPLC), and the developed method exhibited low limits of detection (0.25–0.4 μg L-1), good linearities with correlation coefficients (R2) in the range of 0.9951–0.9996 and satisfactory recoveries ranging from 83.6% to 114.1%, which confirmed the proposed method could be successfully used to determine trace flavonoids in real samples.

Modifying water sorption properties with polymer additives for atmospheric water harvesting applications

Solar-Sorbent based Atmospheric Water Harvesting (AWH) systems are supposed to be a promising key to address the growing concern over global water scarcity. However, it is hard to find a sorbent with all of the necessary characteristics such as high sorption capacity, low regeneration temperature, low corrosion risk, and low cost. Here, we fabricated composites by combining silica gel, salt, and polymers that show faster dynamic, improved regeneration properties and sorption capacity. Adding Polyvinylpyrrolidone (PVP) to silica gel-LiCl composite not only significantly decreases water hold-up in the regeneration process by 35–55%, but also it can increase the sorption capacity. These stable materials also demonstrate higher water harvesting capacities, which makes them proper sorbents in sorption-based technologies. The silica gel-LiCl-PVP capability to be used in a real AWH system is tested in a small prototype and this material could deliver about 0.43 g water per g sorbent. The quality of collected water can meet the global drinking water regulation. The findings also show a good perspective of using these materials in existing systems without any significant costs or modifications. These will reduce the regeneration temperature and consequently the energy consumption will decrease.

Silica nanoparticle surface chemistry: An important trait affecting cellular biocompatibility in two and three dimensional culture systems

Great advantages bestowed by mesoporous silica nanoparticles (MSNs) including high surface area, tailorable pore diameter and surface chemistry, and large pore volume render them as efficient tools in biomedical applications. Herein, MSNs with different surface chemistries were synthesized and investigated in terms of biocompatibility and their impact on the morphology of bone marrow-derived mesenchymal stem cells both in 2D and 3D culture systems. Bare MSNs (BMSNs) were synthesized by template removing method using tetraethylorthosilicate (TEOS) as a precursor. The as-prepared BMSNs were then used to prepare amine-functionalized (AMSNs), carboxyl-functionalized (CMSNs) and polymeric amine-functionalized (PMSNs) samples, consecutively. These nanoparticles were characterized by scanning electron microscopy, zeta potential measurement, dynamic light scattering, BET (Brunauer, Emmett, Teller) analysis, and FTIR technique. In a 3D culture system, stem cells were encapsulated in alginate hydrogel in which MSNs of different functionalities were incorporated. The results showed good biocompatibility for both BMSNs and AMSNs in 2D and 3D culture systems. For these samples, the viability of about 80% was acquired after 2 weeks of 3D culture. When compared to the control, CMSNs caused higher cell proliferation in the 2D culture; while they showed cytotoxic effects in the 3D culture system. Interestingly, polymeric amine-functionalized silica nanoparticles (PMSNs) resulted in disrupted morphology and very low viability in the 2D cell culture and even less viability in 3D environment in comparison to BMSNs and AMSNs. This significant decrease in cell viability was attributed to the higher uptake values of highly positively charged PMSNs by cells as compared to other MSNs. This up-regulated uptake was evaluated by using an inductively coupled plasma optical emission spectroscopy instrument (ICP-OES). These results uncover different interactions between cell and nanoparticles with various surface chemistries. Building on these results, new windows are opened for employing biocompatible nanoparticles such as BMSNs and AMSNs, even at high concentrations, as potential cargos for carrying required growth and/or differentiation factors for tissue engineering applications.

Polymeric Mesoporous Silica Nanoparticles for Enhanced Delivery of 5-Fluorouracil In Vitro.

There is a need for the improvement of conventional cancer treatment strategies by incorporation of targeted and non-invasive procedures aimed to reduce side-effects, drug resistance, and recurrent metastases. The anti-cancer drug, 5-fluorouracil (5-FU), is linked to a variety of induced-systemic toxicities due to its lack of specificity and potent administration regimens, necessitating the development of delivery vehicles that can enhance its therapeutic potential, while minimizing associated side-effects. Polymeric mesoporous silica nanoparticles (MSNs) have gained popularity as delivery vehicles due to their high loading capacities, biocompatibility, and good pharmacokinetics. MSNs produced in this study were functionalized with the biocompatible polymers, chitosan, and poly(ethylene)glycol to produce monodisperse NPs of 36–65 nm, with a large surface area of 710.36 m2/g, large pore volume, diameter spanning 9.8 nm, and a favorable zeta potential allowing for stability and enhanced uptake of 5-FU. Significant drug loading (0.15–0.18 mg5FU/mgmsn), controlled release profiles (15–65%) over 72 hours, and cell specific cytotoxicity in cancer cells (Caco-2, MCF-7, and HeLa) with reduced cell viability (≥50%) over the non-cancer (HEK293) cells were established. Overall, these 5FU-MSN formulations have been shown to be safe and effective delivery systems in vitro, with potential for in vivo applications.

Novel Polymer–Silica Composite-Based Bifunctional Catalysts for Hydrodeoxygenation of 4-(2-Furyl)-3-Buten-2-One as Model Substance for Furfural–Acetone Aldol Condensation Products

Novel bifunctional metal-loaded polymer–silica composite (PSC) catalysts were investigated in the hydrodeoxygenation (HDO) of 4-(2-furyl)-3-buten-2-one (FAc) as a model substance for furfural–acetone aldol condensation products. PSC catalysts were synthesized via a sol–gel method with different polymer contents and subsequently doped with different noble metals. The product composition of the HDO of FAc could be tuned by using catalysts with different polymer (i.e., acidic properties) and metal content (i.e., redox properties), showing the great potential of metal-loaded PSC materials as tunable catalysts in biomass conversions with complex reaction networks. Furthermore, high yields (>90%) of the fully hydrodeoxygenated product (n-octane) could be obtained using noble metal-loaded PSC catalysts in only 8 h of reaction time.

Particle-modified polymeric cladding on glass optical fibers enhances radial light scattering

Radially light-emitting optical fibers are of increasing interest for applications in medicine, visible aesthetics, and environmental remediation. Optical fibers contain a light guiding core coated by protective polymer layers (cladding and coating), which assure both the strength and flexibility of the optical fiber. This paper examines the feasibility of scattering light radially from fibers by loading the fiber cladding with particle scattering centers during the optical fiber fabrication process. This work uses an in-line full-scale scalable facility to coat the fibers and control the polymer cladding and silica sphere. Loadings up to 2.0 wt. % of 500 nm silica particles on the cladding of the optical fiber led to an average of 80 times higher scattering for visible light and up to 30 times higher in the UVA wavelength range compared against cladding without particle modifications. This study illustrated the feasibility of fabricating broadband light scattering optical fibers for use with modified polymeric cladding.

Multifunctional Smart Optical Fibers: Materials, Fabrication, and Sensing Applications

This paper presents a review of the development of optical fibers made of multiple materials, particularly including silica glass, soft glass, polymers, hydrogels, biomaterials, Polydimethylsiloxane (PDMS), and Polyperfluoro-Butenylvinyleth (CYTOP). The properties of the materials are discussed according to their various applications. Typical fabrication techniques for specialty optical fibers based on these materials are introduced, which are mainly focused on extrusion, drilling, and stacking methods depending on the materials’ thermal properties. Microstructures render multiple functions of optical fibers and bring more flexibility in fiber design and device fabrication. In particular, micro-structured optical fibers made from different types of materials are reviewed. The sensing capability of optical fibers enables smart monitoring. Widely used techniques to develop fiber sensors, i.e., fiber Bragg grating and interferometry, are discussed in terms of sensing principles and fabrication methods. Lastly, sensing applications in oil/gas, optofluidics, and particularly healthcare monitoring using specialty optical fibers are demonstrated. In comparison with conventional silica-glass single-mode fiber, state-of-the-art specialty optical fibers provide promising prospects in sensing applications due to flexible choices in materials and microstructures.